Matthew 12:36

But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment--They might say, "It was nothing: we meant no evil; we merely threw out a supposition, as one way of accounting for the miracle we witnessed; if it will not stand, let it go; why make so much of it, and bear down with such severity for it?" Jesus replies, "It was not nothing, and at the great day will not be treated as nothing: Words, as the index of the heart, however idle they may seem, will be taken account of, whether good or bad, in estimating character in the day of judgment."

In this chapter, we have, I. Christ's clearing of the law of the fourth commandment concerning the sabbath-day, and vindicating it from some superstitious notions advanced by the Jewish teachers; showing that works of necessity and mercy are to be done on that day (Mat 12:1-13). II. The prudence, humility, and self-denial of our Lord Jesus in working his miracles (Mat 12:14-21). III. Christ's answer to the blasphemous cavils and calumnies of the scribes and Pharisees, who imputed his casting out devils to a compact with the devil (v. 22-37). IV. Christ's reply to a tempting demand of the scribes and Pharisees, challenging him to show them a sign from heaven (Mat 12:38-45). V. Christ's judgment about his kindred and relations (Mat 12:46-50).

12:36-37 The idle word, in this context, was the accusation that Jesus had demonic inspiration. • What one says will acquit or condemn; one’s words reflect the true condition of the heart.