Can Christians swear and still be Christians?

Technically, yes. Is this type of speech God honoring? No. Swearing is very common in today’s verbal language and sometimes Christians will hear it so often that they start using those words in their speech as well. But what does God think about it? The Bible calls such language a perverse tongue.

Wisdom will save you from the ways of wicked men, from men whose words are perverse.

Proverbs 2:12

To fear the Lord is to hate evil; I hate pride and arrogance, evil behavior and perverse speech.

Proverbs 8:13

Non – Christians notice what you say; the words you choose. They will consider Christianity as a weak ineffective religion because of how you live and what words you use. If you want to show people the power of Christ in your life, then use better words and not a perverse tongue.