Matthew 12:34
You brood of vipers, how can you speak good when you are evil? For the mouth utters what the heart is full of.
Matthew 10:27
what I tell you in the dark, you must utter in the open, what you hear in a whisper you must proclaim on the housetop.
Matthew 28:18-20
Then Jesus came forward to them and said, "Full authority has been given to me in heaven and on earth;
Mark 16:15
And he said to them, "Go to all the world and preach the gospel to every creature:
Acts 18:9-10
And the Lord said to Paul in a vision by night, "Have no fear, speak on and never stop,
Romans 10:14-17
But how are they to invoke One in whom they do not believe? And how are they to believe in One of whom they have never heard? And how are they ever to hear, without a preacher?
Romans 15:18-21
I will not make free to speak of anything except what Christ has accomplished by me in the way of securing the obedience of the Gentiles, by my words and by my deeds,
Ephesians 4:29
Let no bad word pass your lips, but only such speech as is good for edification, as occasion may require, words that are gracious and a means of grace to those who hear them.
2 Timothy 2:2
and transmit the instructions I gave you in presence of many witnesses to trustworthy men, that they may be competent to teach others.
James 3:6
And the tongue is a fire, the tongue proves a very world of mischief among our members, staining the whole of the body and setting fire to the round circle of existence with a flame fed by hell.