A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.
cannot.
Galatians 5:17 For the flesh lusts against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other...
1 John 3:9,10 Whoever is born of God does not commit sin; for his seed remains in him: and he cannot sin, because he is born of God...