Ephesians 4:29 Let no corrupting talk come out of your mouths, but only such as is good for building up, as fits the occasion, that it may give grace to those who hear. And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption. Let all bitterness and wrath and anger and clamor and slander be put away from you, along with all malice. Be kind to one another, tenderhearted, forgiving one another, as God in Christ forgave you.
Psalms 5:9 For there is no truth in their mouth; their inmost self is destruction; their throat is an open grave; they flatter with their tongue.
Psalms 52:2 Your tongue plots destruction, like a sharp razor, you worker of deceit.
Psalms 73:7-9 Their eyes swell out through fatness; their hearts overflow with follies. They scoff and speak with malice; loftily they threaten oppression. They set their mouths against the heavens, and their tongue struts through the earth.
James 3:2-8 For we all stumble in many ways. And if anyone does not stumble in what he says, he is a perfect man, able also to bridle his whole body. If we put bits into the mouths of horses so that they obey us, we guide their whole bodies as well. Look at the ships also: though they are so large and are driven by strong winds, they are guided by a very small rudder wherever the will of the pilot directs. So also the tongue is a small member, yet it boasts of great things. How great a forest is set ablaze by such a small fire! And the tongue is a fire, a world of unrighteousness. The tongue is set among our members, staining the whole body, setting on fire the entire course of life, and set on fire by hell. For every kind of beast and bird, of reptile and sea creature, can be tamed and has been tamed by mankind, but no human being can tame the tongue. It is a restless evil, full of deadly poison.
A small bit in the mouth controls a strong horse. A small rudder turns a large ship. Even so, if we have control over our tongue it is an indication that we have control over our self. Whoever can control the tongue can bridle the whole body. It is possible for something as small as the tongue is to have tremendous power for either good or evil. You don’t solve the problem of an unruly horse by keeping it in the barn, or the problem of a hard-to-steer ship by keeping it tied to the dock. In the same way, even a vow of silence is not the ultimate answer for the misuse of our tongue. If the tongue is like a bit in the mouth of a horse or the rudder on a ship, it leaves us with the question: Who or what holds the reins, or who or what directs the rudder? Some people have no hand on the reins or rudder, and therefore say whatever comes into mind. Others direct their tongue from their emotions or from aspects of their carnal nature. James points us towards having the Spirit of God, working through the new man, set directing hands on the reins and rudder that is our tongue. The untamable tongue is even more dangerous when we consider the deadly poison it can deliver. (Guzik)
What others say to us and what we say to others can last a long time, for good or for evil. The casual sarcastic or critical remark can inflict a lasting injury on another person. The well-timed encouragement or compliment can inspire someone for the rest of their life. We are not told to never speak or to take a vow of silence; in many ways, that would be easier than exercising true self-control over the tongue. The bridle, the rudder, and the fire can all do tremendous good when they are controlled properly. “Pleasant words are like a honeycomb, sweetness to the soul and health to the bones.”