Matthew 7:15-17, 20

“Beware of false prophets who come disguised as harmless sheep but are really vicious wolves. You can identify them by their fruit, that is, by the way they act. Can you pick grapes from thornbushes, or figs from thistles? A good tree produces good fruit, and a bad tree produces bad fruit.

Yes, just as you can identify a tree by its fruit, so you can identify people by their actions.