1. Mose 21:9

Birth of Isaac. - Jehovah did for Sarah what God had promised in Gen 17:6 (cf. Gen 18:14): she conceived, and at the time appointed bore a son to Abraham, when he was 100 years old. Abraham gave it the name of Jizchak (or Isaac), and circumcised it on the eighth day. The name for the promised son had been selected by God, in connection with Abraham's laughing (Gen 17:17 and Gen 17:19), to indicate the nature of his birth and existence. For as his laughing sprang from the contrast between the idea and the reality; so through a miracle of grace the birth of Isaac gave effect to this contrast between the promise of God and the pledge of its fulfilment on the one hand, and the incapacity of Abraham for begetting children, and of Sarah for bearing them, on the other; and through this name, Isaac was designated as the fruit of omnipotent grace working against and above the forces of nature. Sarah also, who had previously laughed with unbelief at the divine promise (Gen 18:12), found a reason in the now accomplished birth of the promised son for laughing with joyous amazement; so that she exclaimed, with evident allusion to his name, "A laughing hath God prepared for me; every one who hears it will laugh to me" (i.e., will rejoice with me, in amazement at the blessing of God which has come upon me even in my old age), and gave a fitting expression to the joy of her heart, in this inspired tristich (Gen 21:7): "Who would have said unto Abraham: Sarah is giving suck; for I have born a son to his old age." מלּל is the poetic word for דּבּר, and מי before the perfect has the sense of - whoever has said, which we should express as a subjunctive; cf. Kg2 20:9; Psa 11:3, etc.

The casting out of Ishmael is here considered of, and resolved on. I. Ishmael himself gave the occasion by some affronts he gave to Isaac his little brother, some think on the day that Abraham made the feast for joy that Isaac was safely weaned, which the Jews say was not till he was three years old, others say five. Sarah herself was an eye-witness of the abuse: she saw the son of the Egyptian mocking (Gen 21:9), mocking Isaac, no doubt, for it is said, with reference to this (Gal 4:29), that he that was born after the flesh persecuted him that was born after the Spirit. Ishmael is here called the son of the Egyptian, because, as some think, the 400 years' affliction of the seed of Abraham by the Egyptians began now, and was to be dated hence, Gen 15:13. She saw him playing with Isaac, so the Septuagint, and, in play, mocking him. Ishmael was fourteen years older than Isaac; and, when children are together, the elder should be careful and tender of the younger: but it argued a very base and sordid disposition in Ishmael to be abusive to a child that was no way a match for him. Note, 1. God takes notice of what children say and do in their play, and will reckon with them if they say or do amiss, though their parents do not. 2. Mocking is a great sin, and very provoking to God. 3. There is a rooted remaining enmity in the seed of the serpent against the seed of the woman. The children of promise must expect to be mocked. This is persecution, which those that will live godly must count upon. 4. None are rejected and cast out from God but those who have first deserved it. Ishmael is continued in Abraham's family till he becomes a disturbance, grief, and scandal to it. II. Sarah made the motion: Cast out this bond-woman, Gen 21:10. This seems to be spoken in some heat, yet…