The Pulpit Commentary - Genesis 21:1-8
The son of promise, or a young child's biography. I. THE BIRTH OF ISAAC 1. A surprising phenomenon . "Who would have said that Sarah should have suckled sons?" " Motherhood at ninety was certainly unusual, especially when conjoined with paternity at a hundred. In a world presided over by a personal Deity there must always be room for surprises. 2. A miraculous production . That the conception and birth of Isaac were due to Divine interposition—that in... read more
John Calvin's Commentary on the Bible - Genesis 21:5
Verse 5 5.And Abraham was an hundred years old. Moses again records the age of Abraham the better to excite the minds of his readers to a consideration of the miracle. And although mention is made only of Abraham, let us yet remember that he is, in this place, set before us, not as a man of lust, but as the husband of Sarah, who has obtained, through her, a lawful seed, in extreme old age, when the strength of both had failed. For the power of God was chiefly conspicuous in this, that when... read more