The first thing to understand is that this was not a case of Ham peeking in the tent, giggling at the sight of his father uncovered, and calling his brothers to come see as well. Verses 24-25 tell us, “When Noah awoke from his drinking and learned what his youngest son had done to him, he said:
"Canaan is cursed. He will be the lowest of slaves to his brothers.”
This confirms that Ham’s act was not a passive one, but an action taken against his father.
But why is the curse pronounced against his son, Canaan?
When read in context with the book of Leviticus, which was also penned by Moses, the author uses the euphemism “uncovered his nakedness” to indicate a sexual act. What’s more, Leviticus 18:7 says, “You shall not uncover the nakedness of your father, which is the nakedness of your mother; she is your mother, you shall not uncover her nakedness.” At least one source, Bryan Fischer of American Family Association, deduces that Ham’s act was actually committing incest with his mother based on the Levitical reference. In his view, the curse on Canaan was because Canaan was the son resulting from this incest.
Other views indicate the sexual sin was against Noah himself and that Ham’s words to his brothers were intended to encourage them to violate their father as well.
Whatever actually transpired, it’s clear from this story that the flood did not wash sin from the earth. The Puritan John Owen stated, “The seed of every sin is in every heart."
We often view the shocking sins of others as if we stand apart and would never do something so awful, but the reality is that, “The heart is deceitful above all things, and desperately wicked; Who can know it?” (Jeremiah 17:9)
Paul tells us in Romans 7:24-25 what our only hope is for this condition: “What a wretched man I am! Who will rescue me from this body of death? Thanks be to God through Jesus Christ our Lord! So then, with my mind I myself am serving the law of God, but with my flesh, the law of sin.”