Matthew 5:37
But let your communication be, Yes, yes; No, no: for whatever is more than these comes of evil.
Nave's Topical Index—AKJV

Matthew 12:35-37
A good man out of the good treasure of the heart brings forth good things: and an evil man out of the evil treasure brings forth evil things.
Nave's Topical Index—AKJV

Ephesians 4:29
Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace to the hearers.
Nave's Topical Index—AKJV

Colossians 3:8
But now you also put off all these; anger, wrath, malice, blasphemy, filthy communication out of your mouth.
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Colossians 4:6
Let your speech be always with grace, seasoned with salt, that you may know how you ought to answer every man.
Nave's Topical Index—AKJV

James 5:12
But above all things, my brothers, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yes be yes; and your no, no; lest you fall into condemnation.
Nave's Topical Index—AKJV