And Noah awoke from his wine, and knew what his younger son had done unto him.

Jamieson-Fausset-Brown Bible Commentary

24. This incident could scarcely have happened till twenty years after the flood; for Canaan, whose conduct was more offensive than that even of his father, was not born till after that event. It is probable that there is a long interval included between these verses and that this prophecy, like that of Jacob on his sons, was not uttered till near the close of Noah's life when the prophetic spirit came upon him; this presumption is strengthened by the mention of his death immediately after.

Matthew Henry's Concise Commentary

9:24-29 Noah declares a curse on Canaan, the son of Ham; perhaps this grandson of his was more guilty than the rest. A servant of servants, that is, The meanest and most despicable servant, shall he be, even to his brethren. This certainly points at the victories in after-times obtained by Israel over the Canaanites, by which they were put to the sword, or brought to pay tribute. The whole continent of Africa was peopled mostly by the descendants of Ham; and for how many ages have the better parts of that country lain under the dominion of the Romans, then of the Saracens, and now of the Turks! In what wickedness, ignorance, barbarity, slavery, and misery most of the inhabitants live! And of the poor negroes, how many every year are sold and bought, like beasts in the market, and conveyed from one quarter of the world to do the work of beasts in another! But this in no way excuses the covetousness and barbarity of those who enrich themselves with the product of their sweat and blood. God has not commanded us to enslave negroes; and, without doubt, he will severely punish all such cruel wrongs. The fulfilment of this prophecy, which contains almost a history of the world, frees Noah from the suspicion of having uttered it from personal anger. It fully proves that the Holy Spirit took occasion from Ham's offence to reveal his secret purposes. Blessed be the Lord God of Shem. The church should be built up and continued in the posterity of Shem; of him came the Jews, who were, for a great while, the only professing people God had in the world. Christ, who was the Lord God, in his human nature should descend from Shem; for of him, as concerning the flesh, Christ came. Noah also blesses Japheth, and, in him, the isles of the gentiles that were peopled by his seed. It speaks of the conversion of the gentiles, and the bringing of them into the church. We may read it, God shall persuade Japheth, and being persuaded, he shall dwell in the tents of Shem. Jews and gentiles shall be united together in the gospel fold; both shall be one in Christ. Noah lived to see two worlds; but being an heir of the righteousness which is by faith, he now rests in hope, waiting to see a better than either.