When God’s promise is finally fulfilled, Abraham’s long-standing fear loses its power. Faith matures from striving and self-protection into trust, integrity, and worship.

1. Promise Kept After Long Delay

• God fulfills His word exactly as spoken:
  • “The LORD visited Sarah as He had said, and the LORD did to Sarah as He had promised.” (Genesis 21:1, ESV)
• Isaac is born when Abraham is 100 and Sarah is 90 (Genesis 21:5; cf. Genesis 12:4).
• The promise waited 25 years, eliminating all human credit (cf. Romans 4:19–21).

2. Faith No Longer Needs a Backup Plan

• Ishmael, born when Abraham was 86 (Genesis 16:16), is now a teenager.
• God commands Abraham to release the son of the flesh:
  • “Whatever Sarah says to you, do as she tells you, for through Isaac shall your offspring be named.” (Genesis 21:12)
• God personally claims responsibility for Ishmael:
  • “I will make a nation of the son of the slave woman also.” (Genesis 21:13)
• Abraham learns to trust God with what he loves but cannot save.

3. Fear Gives Way to Integrity

• Previously, Abraham lied to Abimelech out of fear (Genesis 20:2, 11).
• Now Abimelech asks for an oath:
  • “Swear to me here by God that you will not deal falsely with me.” (Genesis 21:23)
• Abraham responds with honesty and peace, not deception (Genesis 21:24–30).
• Fulfilled promise removes the need for manipulation.

4. Living Securely While Still Waiting

• Abraham sojourns peacefully:
  • “Abraham sojourned many days in the land of the Philistines.” (Genesis 21:34)
• He does not seize land but trusts God’s timing (cf. Genesis 15:18).

5. Worship Rooted in Trust

• Abraham plants a tree and worships:
  • “There Abraham called upon the name of the LORD, the Everlasting God.” (Genesis 21:33)
• God is confessed not merely as Promise-Maker, but as Promise-Keeper over time.

Key Takeaway

• Before Isaac: fear shaped Abraham’s choices.
• After Isaac: faith shapes Abraham’s character.
• When God secures the future, fear loses its grip on the present.

Looking Ahead

Genesis 21 prepares the way for Genesis 22. Only a man who trusts God with everything else can trust Him with Isaac.