When the Pharisees heard that he had silenced the Sadducees, they gathered together, and one of them, a lawyer, asked him a question to test him. "Teacher, which commandment in the law is the greatest?" He said to him, " 'You shall love the Lord your God with all your heart, and with all your soul, and with all your mind.' This is the greatest and first commandment. And a second is like it: 'You shall love your neighbor as yourself.' On these two commandments hang all the law and the prophets."
Jesus' response to the Pharisees is sometimes called the Summary of the Law or the Great Commandment. It reveals the basis of true religion.
True religion starts with loving God, not in some kind of sentimental, feel-good sort of way, but in total commitment of heart, soul, and mind. And so Jesus cites Deuteronomy 6:5 as the greatest and first commandment. That verse from Deuteronomy, of course, is part of the Shema, the basic creed of Judaism. "It means," notes William Barclay, "that to God we must give a total love, a love which dominates our emotions, a love which directs our thoughts, and a love which is the dynamic of our actions."
The second commandment Jesus cites is Leviticus 19:18. Only when we love our neighbor in concrete acts of justice and compassion does our love for God become real and not merely an abstract idea. As Jesus says in the Sermon on the Mount: "You will know them by their fruits" (Matthew 7:16).
In Basic Judaism, Milton Steinberg offers thoughts that are relevant for this passage from Matthew. He writes:
... basic to Judaism is a twofold affirmation concerning God on the one hand and man on the other; the former being that a man shall seek to know God, love Him, revere Him, and do His will; the latter that a man shall love his fellow men also, dealing with them in righteousness and mercy.
What is more, the duality of the attitudes as to God and man is more seeming than real. For to Judaism on love is the obverse and consequence of the other. Piety toward God is meaningless unless it induces compassion toward human beings. (Can one genuinely revere the Creator and not His creation, the Spirit but not Its manifestation?) By the same token, every act of righteousness and mercy reveals the Divinity [image of God] resident within the doer and implies the recognition of an equal Divinity [image of God] touching the person done by.
The simultaneous love of God and man: here is Judaism's first postulate and final inference, its point of departure and its destination, the root of it and its fruitage.
This passage from Matthew shows us just how deeply and thoroughly Jewish Jesus was. And by laying out the basis of true religion in Jewish terms, it also serves as a powerful reminder that the roots of our faith as Christians cannot be torn from its Jewish soil without withering and dying on the vine. Judaism's first postulate and final inference ground Christian faith and mission. And by perfectly keeping these two commandments, Jesus the Jew from Nazareth embodies the point of departure and the destination of true religion. Indeed, Jesus is the incarnation of the Great Commandment.
Some final thoughts on this passage from St. Cyril of Alexandria:
Therefore the first commandment teaches every kind of godliness. For to love God with the whole heart is the cause of every good. The second commandment includes the righteous acts we do toward other people. The first commandment prepares the way for the second and in turn is established by the second. For the person who is grounded in the love of God clearly also loves his neighbor in all things himself. The kind of person who fulfills these two commandments experiences all of the commandments.
May God give us the grace to fulfill these two commandments, that we may experience the blessings of all the commandments.