The Word of God is chock full of commandments. Over 600! So, it might have seemed over the top for Jesus to add a new one to the list.
“A new commandment I give unto you, that you love one another…” (John 13:34a) But this commandment was different on several levels. First, it was targeted. He spoke this to his followers. As believers of Jesus, loving each other becomes the hallmark or trademark of our faith. Second, the commandment starts as an emotional commitment and flows outward to beautiful and supportive action.
So, in reality, this new commandment could encompass all those other 600. Love really does fill in the gaps, helping us pursue God and the good of His followers.