God destroyed every human being on the face of the earth in the Flood except for Noah and his family, eight souls. Our hope would have been that the world had been cleansed of filth and wickedness. But it seems that as soon as these eight came out of the ark, Satan again was able to have his way and sin arose out of those that were considered righteous. Noah planted a vineyard, drank of the wine and lay naked, passed out drunk his tent. Suddenly his sin was compounded when his youngest son, Ham saw his nakedness and told his two brothers outside the tent. The brothers, Shem and Japheth, covered their father by walking backwards so as not to look upon his nakedness.
At first, it seems that the incident with Ham is innocent enough. But when Noah awoke, the scripture says that he “knew what his youngest son had done to him.” Apparently there was more to the story than Ham happening to walk in on his father when he was undressed. Ham did something to Noah that caused Noah to pronounce a curse on one of the sons of Ham but a blessing on the descendants of Shem and Japheth.
But that brings us to the next dilemma. Why would Noah curse Canaan, the youngest son of Ham when it was Ham who committed the sin? First, just as the blessing of Noah was on the descendants of Shem and Japheth, so we must recognize that the curse is not on Canaan the individual, but on Canaan’s descendants. What were Canaan’s descendants like? At look at Leviticus 18 reveals that God listed a large number of marital/sexual prohibitions. One was not allowed to “uncover the nakedness of” any person closer that first cousin. Further, one was not allowed to lie with a man as with a woman nor lie with an animal. Then God said, “for by all these the nations [Canaanites] I am driving I am driving out have been defiled” (Leviticus 18:24). The Canaanites practiced incest, homosexuality, and bestiality. Therefore, when Noah cursed Canaan, he was prophetically cursing the nation that would come from his youngest grandson because his nation would do similar things as Ham had done to him. However, the nations of Shem and Japheth would be blessed.