God says that the people should stop repeating a proverb saying that if parents eat sour grapes their children's teeth will be on edge (meaning the children will experience the consequences of their parents' sins).
People are only responsible for the sins they commit themselves, not for anyone else's.
God defines a righteous person as someone who follows some basic rules: doesn't worship idols, doesn't commit adultery or have sex with his wife while she's menstruating, doesn't oppress people, pays debtors, doesn't charge advance or accrued interest, gives to the needy, avoids iniquity, and obeys God's laws.
How hard can that be?
If the son of a righteous man does these evil things, he'll be punished and die: Papa's good deeds can't save him. It goes both ways: if that wicked guy has a son who is righteous, the son will get a Godly stamp of approval: Papa's sins don't travel down through the generations.
He Doesn't Actually Love Killing People
If the wicked turn away from their wickedness and become righteous, God will forgive them and won't punish them for evil deeds in the past. God wants the wicked to become good, and says he takes no pleasure in their destruction.
But if a righteous person goes bad, God will likewise forget their righteous actions and punish them for their present evil.
God says that the House of Israel claims that his actions aren't fair, which God says is silly, because this whole system is obviously pretty fair.
God urges Israel to change their ways so that they'll escape the judgment coming their way.
Again, God says he doesn't take pleasure in anyone's death. People should quit doing bad stuff, get themselves a new heart and a new spirit, repent for their sins, and live.