Romans 12:14
Bless those who persecute you; bless and do not curse.
Matthew 5:22
But I say to you that anyone who is angry with his brother shall be subject to judgment. And whoever says to his brother, 'Raca,' shall be answerable to the council. But whoever says, 'You fool!' shall be in danger of the fire of hell.
Matthew 5:43-44
"You have heard that it was said, 'You shall love your neighbor and hate your enemy.'
Matthew 12:36
But I tell you that men will have to give account on the day of judgment for every careless word they have spoken.
James 3:6
And the tongue is a fire, a world of evil among the members of the body. The tongue corrupts our whole person, sets the whole course of our life on fire, and is itself set on fire by hell.
James 3:9-10
With it we bless our Lord and Father, and with it we curse men, who have been made in the likeness of God.
1 Peter 2:22-23
"He committed no sin, and no deceit was found in his mouth;"
1 Peter 3:9
Do not return evil for evil or insult for insult, but give a blessing instead; for to this you were called, that you may inherit a blessing.