Sarai began her life in the pagan world of Ur, in the land of the Chaldees, which was located in the area now known as Iraq. She was the half-sister, as well as the wife, of Abram, who would be called Abraham. Sarai and Abram had the same father but different mothers, according to Genesis 20:12. In those days, genetics were purer than they are today, and intermarriage was not detrimental to the offspring of unions between relatives. Also, since people tended to spend their lives clustered together in family units, it was the natural course to choose mates from within their own tribes and families.

When Abram encountered the living God for the first time, he believed Him (Genesis 12:1–4; 15:6) and followed after Him, obeying His command to leave his home to go to a place he had never heard about, much less seen. Sarai went with him.