The Bible on Foul Language

Let there be no filthiness, nor silly talk, nor levity, which are not fitting; but instead let there be thanksgiving. - Ephesians 5:4

Let no evil talk come out of your mouths, but only such as is good for edifying, as fits the occasion, that it may impart grace to those who hear. - Ephesians 4:29

But now put them all away: anger, wrath, malice, slander, and foul talk from your mouth. - Colossians 3:8

Do not accustom your mouth to lewd vulgarity,
for it involves sinful speech. - Sirach 23:13

Pax et bonum