Galatians 4:30 Commentary and Bible Study

Sarah saw what lay behind Ishmael’s mocking and was not willing to tolerate the implied challenge to Isaac’s status as the sole heir of the promise made to Abraham, and she rightly insisted that Ishmael should be driven out and that God’s previously stated purpose should be fulfilled. She had earlier said, ‘It may be that I may obtain children by her’ - Hagar. But now it was clear that Hagar would claim her child for herself and that he was threatening the inheritance of the true child of promise. Radical steps therefore needed to be taken. Scripture commends her for this step even though it seems harsh, for God told Abraham to comply with her request though it distressed him to have to treat his son, Ishmael, in this way (Genesis 21:11). But Paul understands this casting out to be a further part of the allegory represented by the lives of Abraham’s two sons. By these historical events, God taught in an allegory that it is not the natural descendants of Abraham who would be the true heirs of Abraham and of all that God blessed him with, but only the spiritual descendants. These would include more than just physical descendants of Abraham; in fact, like Ishmael, many of the physical descendants would be completely excluded from the promise, for they lacked faith. Ishmael was a physical descendant as much as Isaac, but he had no claim to the promise. The same would be true of many Israelites. Connectedness to Abraham through like-faith is stronger than through physical descent, because those who have a right to be called the children of God are born, ‘not of blood … but of God’ (John 1:13). Consequently, Isaiah says, ‘Doubtless thou art our father; though Abraham be ignorant of us and Israel acknowledge us not, thou, O Lord, art our father, our Redeemer; thy name is from everlasting’ (Isaiah 63:16). The natural descendants would be cast out in favour of the children of promise; God endorses Sarah’s words and makes his choice clear.