en_tn/mat/12/35.md

The good man from the good treasure of his heart produces what is good, and the evil man from the evil treasure of his heart produces what is evil

Jesus speaks about the "heart" as if it were a container that a person fills with good or evil things. This is a metaphor that means what a person says reveals what the person is truly like. If you want to keep this imagery, see the UDB. You can also translate the literal meaning. Alternate translation: "A man who is truly good will speak good things, and the man who is truly evil will speak evil things" (See: rc://en/ta/man/jit/figs-metaphor)