Genesis 21:18

God rescued Hagar and Ishmael in the wilderness and promised them a future (compare 16:7–14). This passage is like chapter 16, but there are key differences. God saves Hagar and Ishmael, but there is no special naming. God repeats the promise to Hagar, but she is not told to return to Sarah.

These repeated themes show God's plan for Hagar and Ishmael. As Joseph later explained to Pharaoh, a repeated event confirms God's plan (41:32). God did not leave Hagar and Ishmael alone. He met them in their time of despair (compare 16:7). He gave them what they needed and promised again that Ishmael would start a great nation (21:13; see 16:11–12).

Paul uses this story in his letter to the Galatians to show that God’s people must let go of anything that could block God’s promise from being fulfilled (Galatians 4:21–31).

God used the incident of Ishmael’s mocking Isaac to separate Ishmael and Hagar from the family and the child of promise. They would constantly threaten the promised descendant if they remained with the family.