John Calvin Commentary Genesis 15:16

"And in the fourth generation they shall come hither again; for the iniquity of the Amorite is not yet full." — Genesis 15:16 (ASV)

The iniquity of the Amorites is not yet full. The reason given here is considered absurd, as it seems to imply that Abram's sons could not be saved except by the destruction of others. I answer that we must modestly and humbly yield to the secret counsel of God.

Since He had given that land to the Amorites for them to inhabit in perpetuity, He intimates that He will not transfer its possession to others without just cause. It is as if He would say, ‘I grant the dominion of this land to your seed without injustice to anyone.’

The land is currently occupied by its lawful possessors, to whom I delivered it. Therefore, until they have deserved by their sins to be rightfully expelled, the dominion of it will not come to your posterity.’ Thus God teaches him that the land must be vacated so that it may be open to new inhabitants.

And this passage is remarkable because it shows that human habitations are distributed in the world in such a way that the Lord will preserve peaceful people, each in their respective places, until they cast themselves out by their own wickedness. For by polluting their dwelling place, they, in a sense, tear away the boundaries fixed by God's hand, which would otherwise have remained unmovable.

Moreover, the Lord here commends His own longsuffering. Even then, the Amorites had become unworthy to occupy the land, yet the Lord not only bore with them for a short time but granted them four centuries for repentance. And so it appears that He does not, without reason, so frequently declare how slow He is to anger.

But the more graciously He waits for people, if, eventually, instead of repenting, they remain obstinate, the more severely does He avenge such great ingratitude.

Therefore Paul says that those who indulge themselves in sin, while the goodness and clemency of God invite them to repentance, heap up for themselves a treasure of wrath (Romans 2:4). And so they reap no advantage from delay, since the severity of the punishment is doubled, just as it happened to the Amorites, whom, eventually, the Lord commanded to be so entirely cut off that not even infants were spared.

Therefore, when we hear that God from heaven is silently waiting until iniquities fill up their measure, let us recognize that this is no time for sluggishness. Rather, let each of us rouse himself, so that we may act before the heavenly judgment arrives.

It was once said by a pagan that God's anger proceeds slowly to avenge itself, but that it compensates for its slowness with the severity of its punishment.

Therefore, there is no reason for the reprobate to flatter themselves when He seems to let them go unnoticed, since He does not rest in heaven in such a way as to cease to be the Judge of the world; nor will He be forgetful of carrying out His office at the proper time.

However, we infer from Moses' words that even though space for repentance is given to the reprobate, they are still devoted to destruction. Some interpret the word עון (ayon) as punishment, as if it meant that punishment was not yet ripe for them. But the first interpretation is more suitable: namely, that they will set no limit to their wickedness until they bring final destruction upon themselves.