Genesis 21:1 Commentary and Bible Study

‘The Lord did unto Sarah as he had spoken.’ You see the way this is repeated over and over again, and the idea is to reinforce it in our minds, that this is an outstanding and a remarkable thing that God has done. The narrator, under inspiration, is labouring the point that everything is happening according to what God had determined and promised. God visited not by means of a vision this time, but by causing Sarah who was barren to conceive. ‘For Sarah conceived, and bare Abraham a son in his old age at the set time which God has spoken to him, and Abraham.’ The faithfulness of God is emphasised here. No word ever comes out of the mouth of God which he does not remember and watch over to fulfil. We can set that word against any number of obstacles and know that it will prevail over them all. Again it is emphasized that this was the child that Sarah bore to Abraham. This important because of Abraham’s previous question to God about Eliezer and God’s answer (Genesis 15:2-4), and because of the shift that Abraham and Sarah had resorted to regarding Hagar (Genesis 17:18-19).Abraham is the head of the family and so Sarah is said to bare him a son; the promises have been made to him and it is God’s word fulfilled to him that is fulfilled. This is a miraculous event for it is ‘at the set time’. Both because of their age, and because of Sarah’s barrenness, they could not have conceived a child naturally. This is what distinguishes Isaac from Ishmael, and what makes Isaac a type of every true believer, born of God, while Ishmael is a type of all who are born naturally. Abraham is still living in the land of the Philistines (Genesis 21:34) and this is where Isaac is going to begin his life.