Expositor's Bible Commentary Commentary Matthew 12:33

"Either make the tree good, and its fruit good; or make the tree corrupt, and its fruit corrupt: for the tree is known by its fruit." — Matthew 12:33 (ASV)

Jesus tells his hearers to make a tree good or bad, knowing that its fruit will be correspondingly good or bad, because a tree is recognized by its fruit. Then Jesus drives the point home. “You brood of vipers” was most likely addressed to the Pharisees in the crowd. Verse 35 makes a tight connection with v.33: what a person truly is determines what that person says and does. Out of the “heart” (GK 2840), the center of human personality, the “mouth speaks,” revealing what is in the heart. How, then, can those who are evil say anything good? What is needed is a change of heart.