Abraham's second wife was Keturah, who bore him six more sons, one of who fostered the medianite tribes, these are the ones who lifted Joseph from the pit, selling him to the the Ishmalites(descendants of Abrahams first son by Sarah's handmaid), who then sold Joseph into Egypt.
Sarah
Abrahams wife
Isaacs mother was Sarah, that is Abrahams wife.
Rebekah was the wife of Abrahams son Iaac.
Lot was Abrahams nephew and not son in law.
The servant was sent to find a wife for Abrahams son Isaac.
Ishmael is his first born by a servant. Issac his second born by his wife.
The narrator is Offred, a Handmaid.
Nothing in The Bible tells us about Sarah (Sari), Abrahams wife and the mother of Isaac.
Ishmael's mother, Hagar, was an Egyptian woman who was a handmaid to Sarah, Abraham's wife. She was given to Abraham as a second wife when Sarah was unable to conceive a child.
The Handmaid's Tale has 324 pages.