(16) The fourth generation.—Heb., dôr. (See Note on Genesis 6:9.) As the four generations are identical with the four centuries of Genesis 15:13, we have here an undesigned testimony to the long duration of human life. So Abram was 100 years old when Isaac was born, and Isaac was 60 at the birth of his children, and Jacob 64 years of age at his marriage. But the word dôr had probably come down from a remote antiquity, and, like the Latin word seculum, signified a century.

The iniquity of the Amorites.—As the chief and leading tribe, they are used here for all the Canaanite nations. We learn from this declaration that the Canaanites were not extirpated by any wilful decree to make room for Israel, but as an act of justice, like that which, because of their moral depravity, overwhelmed the Sethites with a flood. So, subsequently, Israel and Judah had each to bear a punishment in accordance with their sinfulness; and so, throughout the history of the world, whenever nations settle down in vice and corruption, the decay of their institutions follows upon that of their morals, and they either waste away or give place to some more manly race of conquerors. The conquest of Canaan by Israel was parallel to that of the enervated Roman empire of the West by the Germans; only we see the preparation for it. and God’s purpose explained; and we also see that if the Amorites had not made the scale of justice weigh down heavily, they would not have been deprived of their country.

Genesis 15:16. 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.

15:12-16 A deep sleep fell upon Abram; with this sleep a horror of great darkness fell upon him: a sudden change. The children of light do not always walk in the light. Several things were then foretold. 1. The suffering state of Abram's seed for a long time. They shall be strangers. The heirs of heaven are strangers on earth. They shall be servants; but Canaanites serve under a curse, the Hebrews under a blessing. They shall be suffers. Those that are blessed and beloved of God, are often sorely afflicted by wicked men. 2. The judgment of the enemies of Abram's seed. Though God may allow persecutors and oppressors to trample upon his people a great while, he will certainly reckon with them at last. 3. That great event, the deliverance of Abram's seed out of Egypt, is here foretold. 4. Their happy settlement in Canaan. They shall come hither again. The measure of sin fills gradually. Some people's measure of sin fills slowly. The knowledge of future events would seldom add to our comfort. In the most favoured families, and most happy lives, there are so many afflictions, that it is merciful in God to conceal what will befall us and ours.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.

9-21. Take me an heifer, &c.—On occasions of great importance, when two or more parties join in a compact, they either observe precisely the same rites as Abram did, or, where they do not, they invoke the lamp as their witness. According to these ideas, which have been from time immemorial engraven on the minds of Eastern people, the Lord Himself condescended to enter into covenant with Abram. The patriarch did not pass between the sacrifice and the reason was that in this transaction he was bound to nothing. He asked a sign, and God was pleased to give him a sign, by which, according to Eastern ideas, He bound Himself. In like manner God has entered into covenant with us; and in the glory of the only-begotten Son, who passed through between God and us, all who believe have, like Abram, a sign or pledge in the gift of the Spirit, whereby they may know that they shall inherit the heavenly Canaan. In the fourth generation; in the end of the four hundred years mentioned Genesis 15:13, a generation being at that time reckoned at one hundred years, or thereabouts. Or, in the fourth generation numbered from their going into Egypt, or from their leaving Canaan; which may possibly be implied by these words,

they shall come hither. So Caleb was the fourth from Judah, and Moses the fourth from Levi, and so doubtless many others.

The iniquity of the Amorites, i.e. of the people inhabiting Canaan. And the Amorites, one of those people, Genesis 15:21, are here put for all the rest, as Genesis 48:22 1 Kings 21:26 2 Kings 21:2 Amos 2:10, either because they were the greatest and stoutest of all, Amos 2:9, or because Abram dwelt among that people, Genesis 13:18 14:13. All men’s sins are kept by God as in a book of remembrance, not one of them is lost; and as God exactly observes the number and measure of men’s sins, so he determines within himself how far and how long he will bear with sinful men or nations, and what shall be the period of his patience; and when that comes, their measure is full, and their destruction infallibly comes. See Jeremiah 51:13 Matthew 23:32 1 Thessalonians 2:16.

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.

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.