"My dear friends, I am not writing you a new commandment, but reminding you of an old one, one you had from the beginning. This old commandment is the word you have heard." (1 John 2:7)
The commandment to love is not really new. It is an old commandment because it is the first one we learned in the Church, and a new commandment because the world must constantly, and in new ways discover the power of love.