"Either make the tree good and its fruit good, or else make the tree bad and its fruit bad; for a tree is known by its fruit.
Matthew 12:33
Surrounding context
12:32 Anyone who speaks a word against the Son of Man, it will be forgiven him; but whoever speaks against the Holy Spirit, it will not be forgiven him, either in this age or in the age to come.
12:33 "Either make the tree good and its fruit good, or else make the tree bad and its fruit bad; for a tree is known by its fruit.
12:34 Brood of vipers! How can you, being evil, speak good things? For out of the abundance of the heart the mouth speaks.