'Command' in the Bible

I say the following as a concession, not as a command.

I command the married—not I, but the Lord—a wife is not to leave her husband.

However, each one must live his life in the situation the Lord assigned when God called him. This is what I command in all the churches.

About virgins: I have no command from the Lord, but I do give an opinion as one who by the Lord’s mercy is trustworthy.

If anyone thinks he is a prophet or spiritual, he should recognize that what I write to you is the Lord’s command.