How we know Isaac's age when he was “weaned” from Sarah!

Background

How can we understand the age of Isaac when Ishmael mocked him? “And Sarah saw the son of Hagar the Egyptian, which she had born unto Abraham, mocking. Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac.” (Genesis 21:9-10)

Before this can be carefully answered let us step back and get some background. Ishamel was born when Abram was at age eighty-six (Genesis 16:15-16). [Abram was later renamed Abraham at age ninety-nine. (Genesis 17:1-5)] Hagar had been already told by the angel of the Lord that her son would oppose others in Genesis 16:12, “And he will be a wild man; his hand will be against every man, and every man's hand against him; and he shall dwell in the presence of all his brethren.” Yet the Lord also said this about Abraham:

“For I know him, that he will command his children and his household after him, and they shall keep the way of the Lord, to do justice and judgment; that the Lord may bring upon Abraham that which he hath spoken of him.” (Genesis 18:19)

These two pieces are necessary background to understand that Ishmael was stubborn, “a wild man,” and strong-willed, “his hand will be against every man.” But Abraham was also described as one who would teach his own children and give them not only God’s words and moral guidance but also teach them life skills and train them in some beneficial trades. This statement suggested that Abraham would take responsibility for teaching, training, guiding, and preparing his son Ishmael for manhood so that Ishmael would be capable to fulfill God’s purposes for him. Then the announcement came to Abram and Sarai in chapter seventeen for them to have a son from their own marriage. “And I will bless her, and give thee a son also of her: yea, I will bless her, and she shall be a mother of nations; kings of people shall be of her.” (Genesis 17:16) Here Abraham was at age ninety-nine and Ishmael was at age thirteen [99 - 86 = 13].

The same time the next year Isaac was born, “But my covenant will I establish with Isaac, which Sarah shall bear unto thee at this set time in the next year.” (Genesis 17:21) At Isaac’s birth Ishmael was at age fourteen.

And Abraham was an hundred years old, when his son Isaac was born unto him. And Sarah said, God hath made me to laugh, so that all that hear will laugh with me. And she said, Who would have said unto Abraham, that Sarah should have given children suck? for I have born him a son in his old age. And the child grew, and was weaned: and Abraham made a great feast the same day that Isaac was weaned. (Genesis 21:5-8)

Asking an important question

The important question is this, “What year did that feast occur when Ishmael mocked him?” “And the child grew, and was weaned: and Abraham made a great feast the same day that Isaac was weaned.” (Genesis 21:8) Are there some other events in scripture to give insight into this? The answer is yes and it will take a longer journey to present and explain the relevant material.

Many suppose that this term “weaned” merely meant that Isaac was weaned from the breast and that he was certainly old enough to do so. But there are some other things in scripture to point to a specific year which then implied Isaac was past the usual age of weaning from the breast and that an additional kind of weaning was accomplished here. Verse seven in Genesis chapter 21 seems to connect with verse eight but many years intervened because of the expression, “the child grew.” He was not called a babe that grew but a child that grew, and there is a difference. The term “child” could imply he was already weaned from the breast. And then the child grew, and later “was weaned” (verse 8).

What was this weaning? It is suggested and argued herein that this expression “weaned” meant that Isaac was transferred from the primary instruction of his mother Sarah to the primary instruction of his father Abraham. Isaac was transferred from the type of childhood training given to both boys and girls in their early years by their mother and placed under the specific training of a father. Abraham was to train this son up into manhood that he would be well prepared for marriage and fatherhood with all the duties and responsibilites that were detailed in Scripture. Meanwhile girls continued their training under a mother to develop them for future marriage and motherhood.

Examining details

This same kind of event occurred much later in Israel’s history. A woman named Hannah was given the gift of a son after being barren and she nursed and taught her son. Hannah transferred Samuel when “the child was young”, i.e. when he was old enough, to the rearing and training from the high priest at the tabernacle (1 Samuel 1:1–2:11). This was about 750 years later when life spans were distinctly much shorter than Abraham’s 175 years at death. Samuel can be shown to best fit age four for this event.

A special visit by a prophet of God occurred when Samuel was less than twelve years old as shown by the descriptive expression, “child,” he used about himself in verse 26, “And the child Samuel grew on, and was in favour both with the Lord, and also with men.” That expression, “child,” suggested that Samuel was eleven years of age and seven years into his time living at the tabernacle when this prophet's message was given to the older Eli, his sons, and Meraioth's sons. Then God gave these individuals enough time, one whole year (same length as Nebuchadnezzar, Daniel 4:29), to contemplate the message, become repentant, and show repentance with a character and behavior adjustment. Part of their repentance was to carry out the Levitical mandates for personal transgressions and sins of priests given in Leviticus 4:3-12.

The fact that the child Samuel “grew on, and was in favour both with the Lord, and also with men” suggested this period was long enough to prove the character of Samuel. He served seven years, from age four to age eleven, until the prophet's warning came to Eli and his sons. After a year had transpired from that prophecy God visited Samuel and called him at age twelve. Samuel was called at the common age of personal and moral accountability practiced by Judaism. “A Bar or Bat Mitzvah is a coming of age ceremony for Jewish boys and girls when they reach the age of 12 or 13. This ceremony marks the time when a boy or girl becomes a Jewish adult.” [Quoted from https://jewishmuseum.org.uk/schools/asset/life-cycle-bar-bat-mitzvah/]

Another situation to examine came when Abraham married Keturah after Isaac married Rebekah. With Keturah Abraham had six more sons and when they were old enough he sent them out, probably one-by-one. To learn how old they were we must dig even deeper.

Then again Abraham took a wife, and her name was Keturah. And she bare him Zimran, and Jokshan, and Medan, and Midian, and Ishbak, and Shuah. And Jokshan begat Sheba, and Dedan. And the sons of Dedan were Asshurim, and Letushim, and Leummim. And the sons of Midian; Ephah, and Epher, and Hanoch, and Abidah, and Eldaah. All these were the children of Keturah. And Abraham gave all that he had unto Isaac. But unto the sons of the concubines, which Abraham had, Abraham gave gifts, and sent them away from Isaac his son, while he yet lived, eastward, unto the east country. (Genesis 25:1-6)

Abraham had Isaac at age 100 (Genesis 21:1-5), Isaac married Rebekah at age forty (Genesis 24:67; 25:20), Abraham then married Keturah (Genesis 25:1-4), and those six sons were birthed from the same mother. Look at this simple chart following Abraham’s age. In the table below spacing between successive children was averaged at about fourteen and one-half months and perhaps it was even closer than this. With the average child spacing reduced to thirteen months Abraham was about age 146 and five months for Shuah’s birth.

This placed the last son Shuah born when Abraham was age 146 and one-half up to 147 years of age. Then at age eighteen for Shuah Abraham would have been later age 164 up to 165 years old. This point in time would match the time period for Esau and Jacob to have their “weaning” from Rebekah’s training to Isaac’s primary instruction. Because the presence of Ishmael at Isaac’s party caused some friction the departure of Shuah as the last son of Abraham would have been completed before Isaac held this event. Scripture stated, “Abraham gave gifts, and sent them away from Isaac his son, while he yet lived.” The last son, Shuah, was shown to be eighteen to nineteen years old and capable of having been sent out (Genesis 25:6) on his own (same as Ishmael, Genesis 16:15-16; 21:8-14). At this same time period Esau and Jacob could also have had a weaning party or feast at five years of age, like the one given for Isaac.

This larger look at other lives suggested that Ishmael was at age eighteen to nineteen when Abraham held this inheritance and weaning party since Ishmael was old enough to send out as stated. “And Abraham rose up early in the morning, and took bread, and a bottle of water, and gave it unto Hagar, putting it on her shoulder, and the child, and sent her away: and she departed, and wandered in the wilderness of Beersheba.” Now here the term “child” was not meaning he was under age twelve because Ishmael was already age fourteen when Isaac was born. Since it took time for a child to grow enough to wean from the breast Ishmael was at least age sixteen or so for this event.

Note that Ishmael was called a “lad” by God in Genesis 21:12 and 17-20 because he was less than twenty years of age. Twenty years of age was defined as the minimum age to go to war under the Mosaic law (Numbers 1:3, 20, 22, 24), i.e. reaching full manhood. But in the same context (Genesis 21:14-16) Abraham called him a “child” expressing that this son was dear to him. Abraham probably felt it was too soon to send him out into the world. This term “lad” was primarily used in later Scriptures describing those from twelve through nineteen years of age while a “child” was less than age twelve as demonstrated with Samuel’s description of himself.

Remember that Abraham and Sarah were wealthy, they had servants, and an early weaning of Isaac for a prompt return to work was not necessary. This made a later physical weaning quite likely and also a modestly later transfer to male training probable. The parallel of Esau and Jacob about age five for their weaning from a mother’s primary instruction highly suggested it followed the earlier pattern for Isaac and probably many other children in the camp of Abraham.

All of this material as presented did not provide a firm proof but it was consistent within the framework of the Scriptures as laid out. The other and much more firm proof of Isaac’s age of five years for this event came by other pathways. Four sets of Scripture verses show this.

Important time pointers

Genesis 15:13-16 gave 400 years from Ishmael’s mocking of Isaac until the Israelite departure from Egypt. Exodus 12:40 gave 430 years (until the Law was added, Galatians 3:15-17) which began at Abram's journey into Canaan at age 75. Thirty years passed until Isaac was weaned with Abraham at age 105. The remaining 400 years reach from Isaac at age five with his affliction by Ishmael until the exodus from Egypt (Genesis 15:13; 21:8-10, 21; 45:17-18; 47:5-6. This included the afflictions of Exodus 1:8-13 and Pharaoh pursuing them to the Red Sea. Then in a few weeks the Law Covenant was added, Exodus 23–24). From Isaac's weaning / inheritance party 185 years transpired up to entry into Egypt. Then add 215 years for the twelve tribes of Israel dwelling in Egypt until their exit, this summed to 400 years of Genesis 15:13-16 and included the 400 years of Exodus 12:40. When Apostle Paul (aka Rabbi Saul) spoke about this in Acts 13:16-22 and said it was “about 450 years,” (AMP, CEB, CEV, CJB, DRA, ESV, EXB, NET, NIV) he was speaking of two possible ways to derive that number as explained below. [Also see article: The 450 year time period given in Acts 13:17-20]

Acts 13:16-20 (ESV & NIV) described this time period. This period of “about 450 years,” began with Isaac at age five in Acts 13. The beginning 400 year period started when God “chose the fathers” as they dwelt in Canaan, proceeded through when God “made the people great during their stay in the land of Egypt,” and included the exodus from Egypt. Then for “about forty years he put up with them in the wilderness,” added six years “destroying seven nations in the land of Canaan” under Joshua's leadership, and took one more year when he “divided their land to them by lot.”

This summed to a period of about 450 years (400 + 40 + 6 + 1 = 447) that ended after the division of the land by Joshua and Eleazar, the priest (Numbers 34:17; Joshua 13–19 chpts.; Acts 13:19). Some counted the period of about 450 years beginning at Isaac's birth adding five more years (5 + 400 + 40 + 6 + 1 = 452). Both 447 and 452 years were “about the space of four hundred and fifty years” KJV and both fit with “all this took about 450 years” ESV and NIV. As shown, Apostle Paul used the term, “about,” and thereby acknowledged that others used either method of reckoning.

Later Apostle Paul (Rabbi Saul) addressed the early part of this time period, from Abram entering Canaan to the Israelite exodus from Egypt in Galatians 3:15-18 [starting with Abram at age 75 for entry to Canaan up to Isaac’s weaning at age 105 = 30 years; 30 + 400 = 430]. That covenant was the offer to Abram to go to Canaan and God would bless him in Genesis 12:1-3. When Abram departed out of Haran and entered Canaan that covenant was ratified or became effective (Genesis 12:4-5). The year of the exodus from Egypt was 430 years later with the law covenant given about the second month after departure from Egypt.

The meaning of Exodus 12:40

Exodus 12:40 read this way, “Now the sojourning of the children of Israel who dwelt in Egypt was four hundred and thirty years.” But it should be understood in this manner, “Now the sojourning, of the children of Israel (who dwelt in Egypt), was four hundred and thirty years.” This parenthesis and punctuation placed in Exodus 12:40 needed more material to fully explain.

Abraham entered Canaan, went to Sichem, Moreh, Bethel, and passed southward “into Egypt to sojourn there; for the famine was grievous in the land” (Genesis 12:5-10). He was described in Genesis 12:10-20 as sojourning very briefly in Egypt. After this the texts in Genesis (20:1; 21:22-23, 34; 26:1-3; and 35:27) describe both Abraham and Isaac sojourning in the area of Canaan. That Abraham and Isaac were sojourners and not yet owners of the land was evident from Genesis 23:3-18 when it was necessary to purchase from its present owners a field with a cave for burial.

Jacob had lived in Canaan (Genesis 25:26-28), fled north to Haran (Genesis 28:5, 7, 10) and sojourned with Laban (Genesis 32:4) and came back (Genesis 31:25; 33:17) to dwell in Canaan. That Jacob was also a sojourner was verified in Genesis 33:18-20 which recorded that Jacob purchased land to pitch his tent and build an altar to God. Later God directed Israel to enter Egypt (Genesis 46:2-4) where Jacob described his 130 years as a “pilgrimage,” which meant he was a sojourner. Then the eleven sons of Israel spoke to Pharaoh in Genesis 47:4 saying, “For to sojourn in the land are we come; for thy servants have no pasture for their flocks; for the famine is sore in the land of Canaan: now therefore, we pray thee, let thy servants dwell in the land of Goshen.”

This entire sojourn of Abraham, Isaac, Jacob, his sons, and their subsequent offspring began with Abram entering Canaan and after 430 years was completed with the children of Israel leaving Egypt. This was verified by the two statements given in Exodus 6:3-5 and in Hebrews 11:8-10. Thus Genesis 15:13-16, Exodus 12:40, Acts 13:16-20, and Galatians 3:15-18 used the same 400 year period from Isaac at five years of age up to the Israelite departure from Egypt. Thus five very different methods (the narratives about several individual’s lives and the four time summation passages) each pointed to Isaac at age five when his father “Abraham made a great feast the same day that Isaac was weaned” (Genesis 21:8).

Now you can know with certainty the age of Isaac was five years when Ishmael mocked him. Abraham was at age 105 for that event. And Ishmael was late age eighteen to nineteen when sent out under God’s direction and blessing to begin his own life's journey. [See table below.]