The iniquity of the Amorites is not yet full. The reason here given is deemed absurd, as seeming to imply that the sons of Abram could not otherwise be saved, than by the destruction of others. I answer, that we must with modesty and humility yield to the secret counsel of God. Since he had given that land to the Amorites, to be inhabited by them in perpetuity, he intimates, that he will not, without just cause, transfer the possession of it to others; as if he would say, I grant the dominion of this land to thy seed without injury to any one. The land, at present, is occupied by its lawful possessors, to whom I delivered it. Until, therefore, they shall have deserved, by their sins, to be rightfully expelled, the dominion of it sill not come to thy posterity.' Thus God teaches him that the land must be evacuated, in order that it may lie open to new inhabitants. And this passage is remarkable, as showing, that the abodes of men are so distributed in the world, that the Lord will preserve quiet people, each in their several stations, till they cast themselves out by their own wickedness. For by polluting the place of their habitation, they in a certain sense tear away the boundaries fixed by the hand of God, which would otherwise have remained immovable. 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 hence it appears, that he does not, without reason, so frequently declare how slow he is to anger. But the more graciously he waits for men, if, at length, instead of repenting they remain obstinate, the more severely does he avenge such great ingratitude. Therefore Paul says, that they 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 thus they reap no advantage from delay, seeing that the severity of the punishment is doubled; just as it happened to the Amorites, whom, at length, the Lord commanded to be so entirely cut off, that not even infants were spared. Therefore when we hear that God out of heaven is silently waiting until iniquities shall fill up their measure; let us know, that this is no time for torpor, but rather let every one of us stir himself up, that we may be beforehand with the celestial judgment. It was formerly said by a heathen, that the anger of God proceeds with a slow step to avenge itself, but that it compensates for its tardiness by the severity of its punishment. Hence there is no reason why reprobates should flatter themselves, when he seems to let them pass unobserved, [1] since he does not so repose in heaven, as to cease to be the Judge of the world; nor will he be unmindful of the execution of his office, in due time. [2] We infer, however, from the words of Moses, that though space for repentance is given to the reprobate, they are still devoted to destruction. Some take the word vn (ayon) for punishment, as if it had been said that punishment was not yet matured for them. But the former exposition is more suitable; namely, that they will set no bound to their wickedness, until they bring upon themselves final destruction.

Footnotes

1 - "Eo dissimulante."

2 - "Nec officii sui in tempore obliviscatur." The sense given in the translation would perhaps scarcely have been elicited from these words, without the aid of Calvin's own French translation, which thus renders the passage, Et ne s'oublie point de faire son office en temps due.' The Old English version, by adhering to a barely literal rendering, deprives the sentence of all meaning; "neither doth he in time forget his duty." -- Ed

In the fourth age. - An age here means the average period from the birth to the death of one man. This use of the word is proved by Numbers 32:13 - "He made them wander in the wilderness for forty years, until all the generation that had done evil in the sight of the Lord was consumed." This age or generation ran parallel with the life of Moses, and therefore consisted of one hundred and twenty years. Joseph lived one hundred and ten years. Four such generations amount to four hundred and eighty or four hundred and forty years. From the birth of Isaac to the return to the land of promise was an interval of four hundred and forty years. Isaac, Levi, Amram, and Eleazar may represent the four ages.
For the iniquity of the Amorite is not yet full. - From this simple sentence we have much to learn. First. The Lord foreknows the moral character of people. Second. In his providence he administers the affairs of nations on the principle of moral rectitude. Third. Nations are spared until their iniquity is full. Fourth. They are then cut off in retributive justice. Fifth. The Amorite was to be the chief nation extirpated for its iniquity on the return of the seed of Abram. Accordingly, we find the Amorites occupying by conquest the country east of the Jordan, from the Arnon to Mount Hermon, under their two kings, Sihon and Og Numbers 21:21-35. On the west of Jordan we have already met them at En-gedi and Hebron, and they dwelt in the mountains of Judah and Ephraim Numbers 13:29, whence they seem to have crossed the Jordan for conquest Numbers 21:26. Thus had they of all the tribes that overspread the land by far the largest extent of territory. And they seem to have been extinguished as a nation by the invasion of Israel, as we hear no more of them in the subsequent history of the country.

In the fourth generation - In former times most people counted by generations, to each of which was assigned a term of years amounting to 20, 25, 30, 33, 100, 108, or 110; for the generation was of various lengths among various people, at different times. It is probable that the fourth generation here means the same as the four hundred years in the preceding verse. Some think it refers to the time when Eleazar, the son of Aaron, the son of Amram, the son of Kohath, came out of Egypt, and divided the land of Canaan to Israel, Joshua 14:1. Others think the fourth generation of the Amorites is intended, because it is immediately added, The iniquity of the Amorites is not yet full; but in the fourth generation they should be expelled, and the descendants of Abram established in their place. From these words we learn that there is a certain pitch of iniquity to which nations may arrive before they are destroyed, and beyond which Divine justice does not permit them to pass.

But in the fourth generation they shall come hither again: for the (e) iniquity of the Amorites [is] not yet full.
(e) Though God tolerates the wicked for a time, yet his vengeance falls on them when the measure of their wickedness is full.

And in the fourth generation they shall come hither again,.... The seed of Abram were in the land of Canaan before their descent into Egypt; and it is here predicted and promised, that they should come thither again, as they did, in the fourth generation of those that descended thither; for Moses and Aaron were the fourth from Levi, or Eleazar from Kohath, and Caleb from Judah; or rather this was in the fourth age or century from the birth of Isaac, when the four hundred were up before mentioned, men living at that time about an hundred years: Grotius interprets this of the fourth generation of the Amorites, because of what follows:
for the iniquity of the Amorites is not yet full; and therefore as yet would not be turned out of the land, and the seed of Abram could not till then inherit it: wicked people have a measure of iniquity to fill up, which is known of God; some are longer, some are quicker in filling it up, during which time God waits patiently and bears with them; but, when it is completed, he stays no longer, but takes vengeance on them, Matthew 23:32. The Amorites were only one of the nations of the Canaanites, but were a very strong and powerful one, and are put for them all, and are the rather mentioned, because Abram at this time dwelt among them; and it seems as if there were some good men among them, such as the confederates of Abram might be, and they were not arrived to that depth of wickedness they afterwards would and did, and which brought on their ruin, and so made way for the posterity of Abram to inherit their land. Ben Melech interprets it of the punishment of the sin of the Amorites, the time for that was not come to dispossess them of their land.

They shall come hither again - Hither to the land of Canaan, wherein thou now art. The reason why they must not have the land of promise in possession till the fourth generation, is because the iniquity of the Amorites was not yet full. The righteous God has determined, that they shall not be cut off till they are arrived to such a pitch of wickedness; and therefore till it come to that, the seed of Abram must be kept out of possession.