The Greatest Commandments – by Fr Richard Rohr, OFM
Beloved, let us love one another, because love is of God; everyone who loves is begotten by God and knows God. Whoever is without love does not know God, for God is love. In this way the love of God was revealed to us: God sent God’s only Son into the world so that we might have life through him. In this is love: not that we loved God, but that God loved us and sent God’s Son as expiation for our sins. Beloved, if God so loved us, we also must love one another. No one has ever seen God. Yet, if we love one another, God remains in us, and God’s love is brought to perfection in us. —1 John 4:7-12 
“Whoever loves is born of God and knows God.” Unfortunately, many Christians think, “If I read the Bible, I’m born of God; or if I go to church, I know God; or if I obey the commandments, I know God.” Yet John says it’s simply about loving. Note that the converse is true also. “Whoever is without love does not know God, for God is love.”
As the Father loves me, so I also love you. Remain in my love. If you keep my commandments, you will remain in my love, just as I have kept my Father’s commandments and remain in his love. I have told you this so that my joy may be in you and your joy may be complete. This is my commandment: love one another as I love you. No one has greater love than this, to lay down one’s life for one’s friends. You are my friends if you do what I command you. . . . This I command you: love one another. —John 15:9-14, 17 
We might expect Jesus to say, “There is no greater love than to love God.” But he says, “There is no greater love than to lay down your life for your friends.”
Both of these scriptures emphasize the centrality and the importance of love. The beginning and end of everything is love. Only inside of the mystery of love—mutual self-emptying and infilling—can we know God. If we stay outside of that mystery, we cannot know God.
When most of us hear the word “commandment,” we likely think of the Ten Commandments. But Jesus speaks of a “new” commandment surpassing and summing up the “ten” of the Hebrew Bible (Exodus 20:1-17; Deuteronomy 5:6-21): “This is my commandment: Love one another.” He also says: “The entire law and the prophets is summed up in the two great commandments: to love God and to love one another” (see Matthew 22:36-40).
Perhaps we don’t want to hear this commandment because we can never live up to it through our own efforts. We’d like to whittle it down to a little commandment, like “Come to church on Sunday.” But who of us can say we have really loved yet? We’re all beginners. We’re all starting anew every day, and we’re failing anew every day. Loving as imperfect, egoic human beings keeps us in utter reliance upon the mercy, compassion, and grace of God. We can never fully succeed by ourselves.
It seems God gave us a commandment that we could not obey. Perhaps this is so we would have to depend upon the Holy Spirit. This is the greatness, the goodness, the wonder, the impossibility of the Gospel, that it asks of all of us something we—alone, apart, separate—cannot do! Only by living in love, in communion—God in us and we in God (see John 17:20-26)—do we find, every once in a while, a love flowing through us and toward us and from us that is bigger than our own. And we surely know it’s not “we” who are doing it!