The Mouth Reveals the Heart: MacArthur on the Tongue

From John MacArthurs commentary on Colossians:

“When our Lord told the Pharisees that ‘the mouth speaks out of that which fills the heart’ (Matt. 12:34), He gave an important spiritual principle: Speech will reflect the kind of person one is. Because the tongue can speak so easily and is difficult to control, a person’s speech becomes the truest indicator of his spiritual state (cf. Matt. 12:37).

The Bible has much to say about the speech fo both the redeemed ad the unredeemed mouth. The unredeemed mouth is characterized by evil (Prov. 15:28), sexual immorality (Prov. 5:3), deceit (Jer. 9:8), curses (Ps. 10:7), oppression (Ps. 10:7), lies (Prov. 12:22), destruction (prov. 11:11), vanity (2 Pet. 2:18) flattery (Prov. 26:28), foolishness (Prov. 15:2), madness (Eccles. 10:12-13), carelessness (Matt. 12:36), boasting (Ro. 1:30), false doctrine (Titus 1:11), evil plots (Ps. 37:12), hatred (Ps. 109:3), too many words (Eccles. 10:14), and gossip (Prov. 26:22)

In contrast, redeemed speech is characterized by confession of sin (1 John 1:9), confession of Christ (Rom. 10:9-10), edifying speech (Eph. 4:29( talk of God’s law (Ex. 13:9) praise to God (Heb. 13:15), blessing of enemies (1 Pet. 3:9), talk about God (Ps. 66:16), wisdom and kindness (Prov. 31:26), and gentleness (prov. 15:1). It takes as its model the Lord Jesus, who spoke instructively (Matt. 5:2), graciously (Luke 4:22), blamelessly (Luke 11:54), and without deceit (1 Pet. 2:22).” (177-178)