What was the relationship between Sarah and Isaac?
Sarah was the mother of Isaac. She had him when she was already old, as God had promised her. Genesis 21:1-3
What the Bible says
Genesis 21:1
And the Lord visited Sara, as he had promised: and fulfilled what he had spoken.
Genesis 21:2
And she conceived and bore a son in her old age, at the time that God had foretold her.
Douay-Rheims Bible (Challoner revision), public domain.
Did you know?
When Isaac was born, Sarah said that everyone who heard of it would rejoice with her. Genesis 21:6