In words of boastfulness and self-justification there always lie concealed contrariness and pride, from which God turns away. After sinning one ought immediately to 'flee.' But you say, where? To the calm haven of heartfelt repentance.
When the door of steam baths is continually left open, the heat inside rapidly escapes through it; likewise the soul in its desire to say many things, dissipates the remembrance of God through the door of speech, even though everything it says may be good. Ideas of value always shun verbosity, being foreign to confusion and fantasy. Timely silence, then, is precious, for it is nothing less than the mother of the wisest thoughts.
Nothing is more unsettling than talkativeness and more pernicious than an unbridled tongue, disruptive as it is of the soul’s proper state. For the soul’s chatter destroys what we build each day and scatters what we have laboriously gathered together.
A single word made the thief pure and holy, despite all his previous crimes, and brought him into paradise (cf. Luke 23:42-43). A single ill-advised word prevented Moses from entering the promised land (cf. Num. 20:12). We should not suppose, then, that garrulity is only a minor disease. Lovers of slander and gossip shut themselves out of the kingdom of heaven.
How great the evil of pride is, that it deserves to have as its adversary not an angel or other virtues contrary to it but rather God Himself! For it must be noted that it is never said of those who are caught up in the other vices that the Lord resists them, or that the Lord is set against the gluttonous, or fornicators, or the angry, or the avaricious; this is true of the proud alone. For those vices only turn back upon wrongdoers or seem to be committed against those who have a part in them -- that is, against other human beings. This one, however, of its very nature touches God, and therefore it is specially worthy of having God opposed to it.
Nothing so abets our secret destruction as conceit and self-satisfaction, or so cuts us off from God and provokes our chastisement at the hands of other men as grumbling, or so disposes us to sin as a disorderly life and talkativeness.
In general, loquacity opens the doors of the soul, and the devout warmth of the heart at once escapes. Empty talk does the same, but even more so… Empty talk is the door to criticism and slander, the spreader of false rumors and opinions, the sower of discord and strife. It stifles the taste for mental work and almost always serves as a cover for the absence of sound knowledge…
The more a man's tongue flees verbosity, the more his intellect is illumined so as to be able to discern deep thoughts; for the rational intellect is befuddled by verbosity.
Think also of this: the person who is bound to earthly things may rejoice but may also be upset or disturbed or grieved over earthly things: his mind is exposed to continual changes. But the joy of your master (Matthew 25:21) is enduring, for God is unchangeable. Thus control your tongue at the same time as you discipline your body with fasting and strictness. Talkativeness is a great enemy of prayer. A spate of fluttering words stands in the way of the words of prayer. This is the reason that we shall render account for every careless word we utter (Matthew 12:36). One does not bring the dust of the road into a room that one wishes to keep clean; thus keep your heart free from gossip and chatter about the events of the day that is past.