'Law' in the Bible

My loved ones, I do not give you a new law, but an old law which you had from the first; this old law is the word which came to your ears.

Again, I give you a new law, which is true in him and in you; for the night is near its end and the true light is even now shining out.

Everyone who is a sinner goes against the law, for sin is going against the law.

And this is his law, that we have faith in the name of his Son Jesus Christ, and love for one another, even as he said to us.