Matthew 12:34
Generation of vipers, how can you, being evil, speak good things? For out of the abundance of the heart, the mouth speaks.
Matthew 10:27
"What I tell you in darkness, speak in the light: and what you hear in the ear, preach on the house-tops.
Matthew 28:18-20
And Jesus came and spoke to them, saying: All authority in heaven and on earth is given to me.
Mark 16:15
And he said to them: Go into all the world, and preach the gospel to every creature.
Acts 18:9-10
And the Lord spoke to Paul by a vision in the night: Fear not; but speak, and be not silent;
Romans 10:14-17
How, then, shall they call on him in whom they have not believed? And how shall they believe in him of whom they have not heard? And how shall they hear without a preacher?
Romans 15:18-21
For I will not dare to speak of any of those things which Christ has not accomplished through me, by word and deed, in order to make the Gentiles obedient,
Ephesians 4:29
Let no impure speech come out of your mouth, but whatever is good for needful edification, that it may give grace to the hearers:
2 Timothy 2:2
and the things which you have heard from me through many witnesses, these do you commit to faithful men, who shall be able to teach others also.
James 3:6
And the tongue is a fire, the world of iniquity. So is the tongue placed among our members, defiling the whole body, setting on fire the course of life, and being set on fire by hell.