Genesis 21 – Isaac Born, the Bondwoman Cast Out, and the Well of the Oath: Promise Fulfilled, Ishmael Preserved, and Beersheba Established (KJV Bible Study Chart)

Genesis 21 begins by emphasizing exact fulfillment: “the LORD visited Sarah as he had said” and acted “as he had spoken.” Sarah conceives and bears Isaac at the appointed time, when Abraham is one hundred years old. The miracle demonstrates that the covenant heir comes through divine promise rather than human strength. Abraham circumcises Isaac on the eighth day in obedience to Genesis 17, publicly marking the promised son within the covenant household.

Sarah’s laughter has also changed. In Genesis 18 she laughed when the promise appeared impossible; now she declares, “God hath made me to laugh.” What once seemed beyond natural possibility has become historical reality. The chapter therefore gives a powerful demonstration that delay does not equal failure when God has spoken.

After Isaac is weaned, Abraham makes a great feast. Sarah then sees Ishmael “mocking.” She demands that Hagar and her son be cast out because Ishmael is not to inherit with Isaac. Abraham is grieved because Ishmael is his son, but God tells him to hearken unto Sarah and declares, “for in Isaac shall thy seed be called.” This statement becomes important in Romans 9, where Paul distinguishes physical descent from the specific line of promise.

God does not abandon Ishmael. He promises to make a nation of him because he is Abraham’s seed. Hagar and Ishmael enter the wilderness of Beersheba, their water is exhausted, and Hagar expects her son to die. God hears “the voice of the lad,” calls to Hagar, and opens her eyes to a well. Ishmael grows, becomes an archer, dwells in Paran, and receives a wife from Egypt. Divine preservation and covenant succession must therefore remain distinct: God blesses Ishmael while the covenant line continues through Isaac.

Galatians 4 later uses Sarah, Hagar, Isaac, and Ishmael allegorically in contrasting promise and bondage. That inspired application builds upon literal history rather than replacing it. Genesis 21 first records real people and real events; Paul later draws doctrinal significance from them.

The latter portion of the chapter concerns Abimelech and Phichol. They recognize that God is with Abraham and seek an oath of peaceful dealing. Abraham also reproves Abimelech concerning a well seized by his servants. Seven ewe lambs are set apart as witness that Abraham dug the well, and the place is called Beersheba. The name carries associations with both seven and oath, fitting the covenant scene.

Abraham plants a grove at Beersheba and calls upon “the LORD, the everlasting God.” The chapter that began with fulfilled promise ends with worship. God has given Isaac, preserved Ishmael, established Abraham, and proven again that His covenant purpose advances according to His Word rather than human timing.