Proverbs 18:21 NIV

2 Corinthians 11:15 NIV
It is not surprising, then, if his servants also masquerade as servants of righteousness. Their end will be what their actions deserve.

2 Peter 2:18 NIV
For they mouth empty, boastful words and, by appealing to the lustful desires of the flesh, they entice people who are just escaping from those who live in error.

Colossians 4:6 NIV
Let your conversation be always full of grace, seasoned with salt, so that you may know how to answer everyone.

Ecclesiastes 10:12-14 NIV
Words from the mouth of the wise are gracious, but fools are consumed by their own lips. At the beginning their words are folly; at the end they are wicked madness—     and fools multiply words. No one knows what is coming— who can tell someone else what will happen after them?

Ephesians 4:29 NIV
Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen.

Isaiah 57:19 NIV
    creating praise on their lips. Peace, peace, to those far and near,” says the Lord. “And I will heal them.”

James 3:6-9 NIV
The tongue also is a fire, a world of evil among the parts of the body. It corrupts the whole body, sets the whole course of one’s life on fire, and is itself set on fire by hell. All kinds of animals, birds, reptiles and sea creatures are being tamed and have been tamed by mankind, but no human being can tame the tongue. It is a restless evil, full of deadly poison. With the tongue we praise our Lord and Father, and with it we curse human beings, who have been made in God’s likeness.

Matthew 12:35-37 NIV
A good man brings good things out of the good stored up in him, and an evil man brings evil things out of the evil stored up in him. But I tell you that everyone will have to give account on the day of judgment for every empty word they have spoken. For by your words you will be acquitted, and by your words you will be condemned.”

Proverbs 10:19-21 NIV
Sin is not ended by multiplying words, but the prudent hold their tongues. The tongue of the righteous is choice silver, but the heart of the wicked is of little value. The lips of the righteous nourish many, but fools die for lack of sense.

Proverbs 10:31 NIV
From the mouth of the righteous comes the fruit of wisdom, but a perverse tongue will be silenced.