'Command' in the Bible

I say this as a concession, not as a command.

To the married I give this command -- not I, but the Lord -- a wife should not divorce a husband

With regard to the question about people who have never married, I have no command from the Lord, but I give my opinion as one shown mercy by the Lord to be trustworthy.

If anyone considers himself a prophet or spiritual person, he should acknowledge that what I write to you is the Lord's command.