John Calvin Commentary Genesis 21:20

"And God was with the lad, and he grew. And he dwelt in the wilderness, and became, as he grew up, an archer." — Genesis 21:20 (ASV)

And God was with the lad. There are many ways in which God is said to be present with people. He is present with his elect, whom he governs by the special grace of his Spirit; he is present also, sometimes, as it concerns external life, not only with his elect, but also with strangers, in granting them some significant blessing: as Moses, in this place, commends the extraordinary grace by which the Lord declares that his promise is not void, since he showed favor to Ishmael, because he was the son of Abraham.

From this, however, this general doctrine is inferred; that it is to be entirely ascribed to God that people grow up, that they enjoy the light and common breath of heaven, and that the earth supplies them with food. Only it must be remembered, the prosperity of Ishmael flowed from this cause, that an earthly blessing was promised him for the sake of his father Abraham.

In saying that Hagar took a wife for Ishmael, Moses refers to civil order; for since marriage forms a principal part of human life, it is right that, in contracting it, children should be subject to their parents and should obey their counsel. This order, which nature prescribes and dictates, was, as we see, observed by Ishmael, a wild man in the barbarism of the desert; for he was subject to his mother in marrying a wife.

From this we perceive what a prodigious monster the Pope was, when he dared to overthrow this sacred right of nature. To this is also added the impudent boast of authorizing a wicked contempt of parents, in honor of holy wedlock. Moreover, the Egyptian wife was a kind of prelude to the future dissension between the Israelites and the Ishmaelites.