"Which is the first of all the commandments?"

Jesus replied, "The first is this:

Hear, O Israel!
The Lord our God is Lord alone!
You shall love the Lord your God with all your heart,
with all your soul, with all your mind,
and with all your strength.
The second is this:
You shall love your neighbor as yourself.
There is no other commandment greater than these."

-- Mk 12:28-34

In response to the question about the first of the commandments, Jesus says: "The first is, 'Hear, O Israel: The Lord our God, the Lord is one; and you shall love the Lord your God with all your heart, and with all your soul, and with all your mind, and with all your strength.' The second is this, 'You shall love your neighbor as yourself.' There is no other commandment greater than these."

The apostle St. Paul reminds us of this: "He who loves his neighbor has fulfilled the law. The commandments, 'You shall not commit adultery, You shall not kill, You shall not steal, You shall not covet,' and any other commandment, are summed up in this sentence, 'You shall love your neighbor as yourself.' Love does no wrong to a neighbor; therefore love is the fulfilling of the law."

-- CCC 2196

"Hear, O Israel, the LORD our God is one LORD..." (Dt 6:4; Mk 12:29). "The supreme being must be unique, without equal. . . If God is not one, he is not God" (Tertullian, Adv. Marc., 1, 3, 5: PL 2, 274).

-- CCC 228

(Celebrating the Year of Saint Paul. The Apostle likely walked the Roman forum, pictured here, the center of the life of the empire and key to understanding the challenges faced by the first Christians, many of whom were martyred like Paul and the Apostle Peter for witnessing to their Faith in Jesus Christ. Photo by author.)