The Abraham and Sarah unit uses the Bible story included in Genesis 12; 13:1-4, 12; 17; 18:1-15; 21:1-8. At God's call, Abram and Sarai left Haran for Canaan. God promised land and a son to a man already 75 years of age. Abram trusted God and waited for the promise. Sarai was also very old and fulfilled her duty to provide her husband a child by following a culturally acceptable practice. She gave Abram her maid Hagar to conceive a child. The child who was born--Ishmael--would have been considered Sarai's by custom. Ishmael was not the son God had promised, however.
God told Abram to change his name to "father of nations" and Sarai's to "princess" because she would be a mother of nations. God promised they would have a son in the next year. Abram laughed to himself and suggested, "Why not let Ishmael be my heir?" God sent three visistors and spoke again, promising a son in nine months. Twenty-five years after Abram left Haran, Sarah bore a son. They called him "Isaac."
Scriptures: Genesis 12; 13:1-4, 12; 17; 18:1-15; 21:1-8