What does it mean that "the sin of the Amorites has not yet reached its full measure" (Genesis 15:16)?

In the fourth generation Israel would return to the land of Canaan v.16), because only then would "the iniquity of the Amorites" be complete. God tells Abram this because He intended to dispossess the Amorites of their land in order for Israel to possess it, but would not do so until the wickedness of that nation had risen to a height that required the judgment of God.

Before we leave Genesis 15 note two things. First, God was going to permit the Amorites to fill up the cup of their iniquity before he ejected and destroyed them. This is ever the way He takes in His holy government, and it accounts for the long-suffering He extends to the guilty world in which we are living. He knows the full nature of man's evil from the outset, but He allows it to be fully developed, so that His judgment, when it falls in full severity, may be justified in the sight of all created intelligences.

It may be needful to say a word perhaps upon verse 16, "for the iniquity of the Amorites was not yet full," seeing that so many of the Lord's people of this day have no idea of God allowing iniquity to come to the full; but on the contrary, are expecting evil to diminish and gradually to cease. If we transfer this principle of the growth of evil from the Old Testament to the New, or even from Genesis 15 to 2 Thessalonians, we shall perhaps discover what a measure of insubjection of mind still exists in reference to the character and growth of the evil described in chapter 2 "For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way, and then shall that wicked one be revealed, whom the Lord shall consume with the Spirit of his mouth and destroy with the brightness of his coming." For, "God shall send them strong delusions that they should believe a lie, that they all might be damned who believe not the truth, but had pleasure in unrighteousness." Indeed it is difficult to conceive how a revelation from God, closing as the New Testament does with the Apocalyptic woes and vials and trumpets and plagues, can be understood in any other way than of the coming judgment upon a widespread apostasy, or as Abram in his day was taught in the fact that the "iniquity of the Amorites was not yet come to the full."

It is not thus that I should present my thought, for God is far from suppressing an economy as soon as man has failed to fulfil his duty under this economy. God uses long forbearance. He employs all sorts of means to recall man to his duty, until, as it is expressed in the word, there is no remedy. This is what He has shewn even with regard to those who did not enjoy a covenant, announcing to Abraham that his seed should go down into Egypt; and God adds that it should not yet possess the promised land, because the iniquity of the Amorites was not yet full (Gen. 15:13-16).

It is a day of judgment. The vengeance of righteousness is to be executed on the Amorites, who had now filled up the measure of their sins. The long suffering of God had now no longer to wait (Gen. 15:16).

It is a day of judgment on these nations, as the day of Noah had been on the world before the flood, or the day of Lot on the cities of the plain, or the day of Moses on the land of Egypt. Joshua's sword, as we have already said, is to be interpreted as that of a judge, rather than that of a conqueror. The giving of their inheritance to the children of Abraham may appear to be the principal cause of this great action, but it is really grounded on the fact that the iniquity of the Amorites was now full. The sword of conquest for Israel is the sword of judgment on the Canaanites — and the people of the Lord had to wait on the ripening of the nation's sin and the judgment of the Lord, ere they could attain their inheritance (see Gen. 15:16).

The apostle then tells us that the day of the Lord cannot come until the apostasy, and the revelation of "the man of sin." That is perfectly plain. The Lord told Abram, as a reason for not judging the Amorites, that the cup of their iniquity was not yet full. The cup of Sodom and Gomorrah was filled, as we know, but that of the Amorites was not. They were allowed to follow their evil courses until the earth was ready to spue them out, and then the sword of retribution fell upon them at God's command. It is always a principle in God's dealings that the iniquity which He judges must be thoroughly out. The lawlessness of Christendom is not thoroughly open. There is still, in the midst of a great deal that is very sad, a great deal of conversion going on. There is also not a little of devotedness to Christ. The forms and the reality of truth are yet apparent, and it is as yet "the mystery of lawlessness." It will be a totally different thing in that day.

As regards the church of God, there is much more difficulty in believing that there will be the utter and final rejection of it, although of course it is only of the professing church that this will be true. It is a solemn truth, when evil comes in at the beginning, that it goes on increasing and ripening until judgment comes; and mark, also, that judgment is not executed upon it until it is fully ripe - "The iniquity of the Amorites is not yet full." This principle is fully and plainly set forth in the parable of the tares. The tares were sown at the beginning, but were not to be rooted up at once. Both the tares and the wheat were to grow together until the harvest. Thus the Lord declares positively that the mischief came in at the beginning, and would go on ripening till the execution of judgment. It is not a question of individuals, or whether the wheat will be all gathered into the garner (that of course it will be), but that the public testimony is spoiled. The crop was spoiled in the field; and that could not be remedied by man, for, looked at as a crop in the field, man is not competent to remedy it, for man is not competent to judge it. Besides, our business is grace and not the rooting up of tares.

This, we believe, is always God's way. He does not act in judgment until the evil is fully manifested. It was so with the Amorite nations, as shown in Genesis 15:16. It was so with the kings and people in Jerusalem, as testified in 2 Chronicles 36:- 11-20. It will be so again in the sad history of Christendom, as predicted in Revelation 17 and 18.

Notice, the vessels of wrath fit themselves to destruction—God is not responsible for man’s sin, but holds man responsible for it. He endures with much long-suffering, so that when His wrath falls it may be deserved to the full and righteously meted out. For instance, be endured the Amorites for four hundred years, till the cup of their iniquity was full.

233 Having given this general view of the connection of the whole subject, I return to the conquest of Canaan. The scriptures are express in presenting it as an example of God's positive judgment after all patience had already been shewn to be useless (as in the case of Sodom and Gomorrha); of His power against the enemies of His nature, purposes, and people; and of His faithfulness to these last. Abraham was told that his descendants must go down and dwell in Egypt for a long period, for the iniquity of the Amorites was not yet full; and this took place. Israel was clearly informed of the cause why they were thus judged: "Not for thy righteousness, or for the uprightness of thine heart, but for the wickedness of these nations, the Lord doth drive them out before thee," Deut. 9:5; Deut. 18:12. This truth is expressed in the strongest possible manner (Lev. 18) in warning Israel not to fall into the like abominations. "And the land is defiled, therefore I do visit the iniquity thereof upon it, and the land itself vomiteth out her inhabitants. Ye shall therefore keep my statutes … that the land spue not you out also, when ye defile it, as it spued out the nations that were before you." Thus a people, allowed to ripen up to their full height of wickedness, are taken as the occasion of shewing God's righteous wrath and power. Israel is fully warned and apprised of the principle on which it was done. It is a great public sample of God's full judgment in the earth. They were to be destroyed by the judicial power of God. It was also (as the case of Achan fully shews) the occasion of shewing God's power and faithfulness, but His strict judgment of evil in the midst of His people.