Mc 12:28-31
One of the scribes, when he came forward and heard them disputing and saw how well he had answered them, asked him, "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.".