5 And Abraham was one hundred years old when Isaac his son was born to him.
Genesis 21:5 Cross References - LEB
Genesis 17:1
1 When* Abram was ninety-nine years old Yahweh appeared to Abram. And he said to him, "I am El-Shaddai;* walk before me and be blameless
Genesis 17:17
17 And Abraham fell upon his face and laughed. And he said in his heart, "⌊Can a child be born to a man a hundred years old⌋,* or ⌊can Sarah bear a child at ninety⌋?"*
Romans 4:19
19 And not being weak in faith, he considered his own body as good as dead, * because he* was approximately a hundred years old, and the deadness of Sarah's womb.