“Then the LORD took note of Sarah as He had said, and the LORD did for Sarah as He had promised. So Sarah conceived and bore a son to Abraham in his old age, at the appointed time of which God had spoken to him. Abraham called the name of his son who was born to him, whom Sarah bore to him, Isaac.” – Gen. 22:1-3
God remembered Sarah, just as before he remembered Noah, and Abraham (Gen. 8:1; 19:29).
The promise from Genesis 15:4 is finally fulfilled after many years; Isaac is born. This promise was repeated by God in 17:16, and Isaac was named by God Himself in 17:19. Isaac was the promised son with whom God would establish His covenant (17:21). So we see that despite extenuating circumstances (i.e., Abraham and Sarah’s age) God brings to pass what He promises. The birth of Isaac was doubly significant in that through him would come Abraham’s descendants; and Abraham’s descendants would receive the Promised Land, which God spoke of in Gen. 12:7.
The language in verse three appears overly purposeful in its clarity:
“Abraham called the name of his son who was born to him, whom Sarah bore to him, Isaac.”
The text may have been written as such to remove any ambiguity about who the father of Isaac was (due to the situation with Sarah and Abimelech in Genesis 20), and additionally to enforce that Isaac is identified as the only ‘legitimate’ son that Abraham had with Sarah. Ishmael was born to Abraham, but through Hagar, not Sarah. The Muslim faith generally holds that not Isaac, but Ishmael was the son of promise whom Abraham offered to sacrifice to God.
A Note on the Years of Abraham’s Life
The Oxford Jewish Study Bible explains that Abraham’s life was divided into seven 25-year periods, totaling his 175 years (Gen. 25:7). The first three periods were in Mesopotamia until he left Haran (Gen. 12:4), then one period without the promised son in Canaan (Gen. 12:5 – 21:2), and three periods in Canaan after Isaac’s birth (21:3-25:8). The 25 years when he had the promise and it remained unfulfilled cover the majority of the biblical narrative.
This is fascinating to note, as it tells us that the shaping of Abraham’s faith through trials, coupled with the hope and promise of the future, is the important part of the message the scriptures reveal to us. This largely parallels the New Testament writings, as we read about the beginnings of the church, and the trials of the apostles, only to catch a glimpse of the world to come in the Revelation of St. John.
The whole New Testament concept of somehow living here in this world, and yet at the same time partaking of the Kingdom of God is much like Abraham’s living in the Promised Land; though it would never really belong to him in any tangible way in his lifetime, what Abraham really had was the hope and promise of the future.