Problem: How many children did Abraham have, one or two?Genesis 22:2, Hebrews 11:17, and Galatians 4:22 tell us different things. What about Ishmael and Isaac? Aren’t they both the children of Abraham?
Solution:
Abraham had one son
Genesis 22:2, “And He said, ‘Take now your son, your only son, whom you love, Isaac, and go to the land of Moriah; and offer him there as a burnt offering on one of the mountains of which I will tell you.’”
Hebrews 11:17, “By faith Abraham, when he was tested, offered up Isaac; and he who had received the promises was offering up his only begotten son.”
Abraham had two sons
Galatians 4:22, “For it is written that Abraham had two sons, one by the bondwoman and one by the free woman.”
The answer to this apparent contradiction is found in understanding the typological representation of Isaac, Abraham’s second-born son, as a type of Christ. Abraham had Ishmael by the handmaiden Hagar. But Isaac was the child of promise, not Ishmael: “But God said to Abraham, ‘Do not be distressed because of the lad and your maid; whatever Sarah tells you, listen to her, for through Isaac your descendants shall be named,’” (Gen. 21:12).
If you look at the chart below, you will see the similarities between Isaac and Jesus. In other words, Isaac was a prophetic representation of Jesus. This is why Jesus said, “Your father Abraham rejoiced to see My day, and he saw it and was glad,” (John 8:56). Abraham had, in a very real sense, seeing the gospel presentation in the offering of his son, his “only begotten.” So, we see here that the term “only begotten” is in reference to the unique son of God and Isaac was acting out the sacrifice of Christ, prophetically.
Also, Abraham had six other sons besides Ishmael and Isaac through his wife Keturah whom he married after Sarah died. “Now Abraham took another wife, whose name was Keturah. 2 And she bore to him Zimran and Jokshan and Medan and Midian and Ishbak and Shuah,” (Gen. 25:1-2). Obviously, this was known by the writers of Genesis as well as Hebrews and Galatian
