<p>12:34&nbsp;<em>You offspring of vipers</em>- A clear allusion to the Jews as the seed of the serpent of Gen. 3:15 who would be the ones who would be in conflict with the seed of the woman, the Lord Jesus.</p>
<p><em>How can you-</em>&nbsp;Because of the principle that who we are internally is ultimately reflected by our external actions and words (:33), it was impossible that their 'good words' could be sincere because the other fruit of their lives showed they were rotten within. &quot;How can you...&quot;&nbsp; doesn't mean that they could not change. It means that given their present internal condition, they could never speak good things. The 'good word' which the context has in view is the confession that Jesus of Nazareth is God's Son; the evil word was that He was Satan's agent. This wrong judgment of Jesus' identity was because of their evil heart. Their doctrinal mistake was a reflection of their internal fleshly thinking. The Lord said that the Jews were evil, and therefore good things could not come from them (Mt. 12:34; 7:17-20). And yet He also said, presumably with the same audience in mind, that although they were evil, they potentially knew how to give good things, e.g. to their children; and therefore how much could God give them good things if they repented (Mt. 7:11).</p>
<p><em>Being evil speak good things-</em>&nbsp;This may be an intensive plural, 'the good thing'. The good thing to be spoken was the confession that Jesus was Son of God. John's Gospel emphasizes this, and Rom. 10:9,10 suggests that a verbal confession of Jesus as Lord was required in the conversion process: &quot;if you shall confess with your mouth Jesus as Lord, and shall believe in your heart that God raised him from the dead, you shall be saved. For with the heart man believes to righteousness, and with the mouth confession is made to salvation&quot;. This confession was likely made at baptism, as in the case of the Ethiopian eunuch. We must ever remember that Matthew's gospel is the transcript of his preaching of the Gospel; it was a missionary document, intended to bring forth the confession that Jesus is Lord and Son of God. This is not to say that the Lord's teaching here does not establish basic principles regarding the connection between thought and speech. It does. But the specific context is of confessing that He is Lord rather than of Satan.&nbsp;</p>
<p><em>For out of the abundance of the heart the mouth speaks-</em>&nbsp;Gk. 'that which remains'. The idea may be that a certain amount of human thought is taken up with basic human functioning, but that which remains over and above that, the part of our thinking which we can consciously control, is what must be controlled- for it is that part of our thinking which controls the words and actions which are the fruit on the tree of a man's life (:33).</p>