'Commandment' in the Bible

Dear friends, I am not writing to you a new commandment, but an old commandment that you have had from the beginning. This old commandment is the word you have heard.

On the other hand, I am writing to you a new commandment that is truly in him and in you. For the darkness is fading away, and the true light is already shining.

And this is his commandment: to believe in the name of his Son, Jesus the Messiah, and to love one another as he commanded us.

And this is the commandment that we have from him: the person who loves God must also love his brother.