Matthew 12:33

Either make the tree good - That is, the effect will be always similar to the cause; a bad tree will produce bad fruit, and a good tree, good fruit.

The works will resemble the heart: nothing good can proceed from an evil spirit; no good fruit can proceed from a corrupt heart. Before the heart of man can produce any good, it must be renewed and influenced by the Spirit of God.

Either make ... - The fact asserted in this verse is, that a tree is known, not by its leaves, or bark, or form, but by its fruit. The application to the argument is this: "You are to judge of man's being in league with Satan by his works. If my doctrines and works be properly the works of Satan, then I am corrupt; if not, then your charge is blasphemy. So, on the other hand, if, notwithstanding your professions, your works are the works of the devil, and your doctrines are such as he would teach, it would prove respecting you that which you charge on me." In this indirect but powerful manner he advances to the charge against them, which he urges in the following verses.

12:33 Either make the tree good and its fruit good: or make the tree corrupt and its fruit corrupt - That is, you must allow, they are both good, or both bad. - For if the fruit is good, so is the tree; if the fruit is evil, so is the tree also. For the tree is known by its fruit - As if he had said, Ye may therefore know me by my fruits. By my converting sinners to God, you may know that God hath sent me. Matthew 7:16 ; Luke 6:43.