Abraham and Sarah were originally named Abram and Sarai, but, for some strange reason, God changed their names
in chapter 17 of Genesis (17:5, 15) to Abraham and Sarah.
To avoid confusion, I'll use
their new, more familiar, God-given names in the notes.
See notes: Gen 11:26, 12:1,
13:1, 15:1, 16:1,