John Piper, in a sermon, The New Commandment of Christ: Love One Another As I Have Loved You”:
If you are a follower of Jesus, a Christian, a child of God through faith in Christ, you are a person under authority. You are not your own. You do not call the shots any more. Jesus is more to you than Master of your life, but he is not less. He comes to you with more than commandments, but not less. You are a person whose life is defined by the will of another, namely, Jesus. What he wills you want.
And what he wills and commands in this verse is that we love each other—that his followers love each other. “A new commandment I give you”—not a new suggestion, or a new idea, or a new possibility, or a new life-option, but a new commandment.
What’s New About Jesus’ New Commandment?
The question that has guided all my focus in this message is What’s new about the commandment to love each other? “A new commandment I give to you, that you love one another.” I see two answers implied in this verse. The key to the answers is found in the words in the second half of the verse: “. . . just as I have loved you, you also are to love one another.” The newness of the command to love each other is found in the words “as I have loved you.”
I see two ways that the commandment to love each other is new in those words. First, the command is new because it is a command to live out the love of Jesus. Second, the command is new because it is a command to live on the love of Jesus. The words “as I have loved you” contain a pattern for our love for each other, and they contain a power for our love for each other.
Loving each other is not a new command per se. It was already there in the Old Testament (Leviticus 19:18, “You shall love your neighbor as yourself”). What’s new is that Jesus is now the pattern we live by and the power we live on. Let’s look at these two kinds of newness.
Knowing God through His Word ... Day by Day 