What does the Bible say about curses on people?

Proverbs 17:13 (NLT)

If you repay good with evil,

evil will never leave your house.

Sowing and reaping is something that hits believers and unbelievers. However, as a believer we can confess our sins and be washed from them.

As an unbeliever, this is not so. People who do evil bring curses upon themselves.