John Calvin Commentary Galatians 4:30

"Howbeit what saith the scripture? Cast out the handmaid and her son: for the son of the handmaid shall not inherit with the son of the freewoman." — Galatians 4:30 (ASV)

But what says the Scripture? There was some consolation in knowing that we only share the lot of our father Isaac; but it is a still greater consolation when he adds that hypocrites, with all their boasting, can gain nothing more than to be cast out of the spiritual family of Abraham; and that, to whatever extent they may harass us for a time, the inheritance will certainly be ours. Let believers cheer themselves with this consolation, that the tyranny of the Ishmaelites will not last forever. They appear to have reached the highest pre-eminence and, proud of their birthright, look down upon us with contempt; but they will one day be declared to be the descendants of Hagar, the sons of a slave, and unworthy of the inheritance.

Let us be instructed by this beautiful passage, “not to fret ourselves because of evil-doers,
neither be envious against the workers of iniquity” (Psalms 37:1), when they hold a temporary habitation and rank in the Church, but patiently to look for the end which awaits them.

There are many pretended Christians, or strangers, who hold a place in the Church, but who afterwards give evidence of their departure from the faith, as he who, proud of his birthright, at first reigned, was cast out like a foreigner with the posterity of Ishmael.

Some censorious persons smile at Paul’s simplicity in comparing a woman’s passion, arising out of a trifling quarrel, to a judgment of God. But they overlook the decree of God, which took effect in such a manner as to make it manifest that the whole transaction was directed by a heavenly providence.

That Abraham should have been commanded to humor his wife (Genesis 21:12) entirely in the matter is undoubtedly extraordinary, but it proves that God employed the services of Sarah for confirming his own promise. In a word, the casting out of Ishmael was nothing other than the consequence and the accomplishment of that promise, “In Isaac shall thy seed be called” (Genesis 21:12)—not in Ishmael. Therefore, although it was the avenging of a woman’s quarrel, God nonetheless made known his sentence by her mouth as a type of the Church.