+ Mk 12: 28-34
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.”
The scribe said to him, “Well said, teacher. You are right in saying, ‘He is One and there is no other than he.’
And ‘to love him with all your heart, with all your understanding, with all your strength, and to love your neighbor as yourself’ is worth more than all burnt offerings and sacrifices.”
And when Jesus saw that (he) answered with understanding, he said to him, “You are not far from the kingdom of God.” And no one dared to ask him any more questions.
The New American Bible
The Catechism of the Catholic Church
129 Christians therefore read the Old Testament in the light of Christ crucified and risen. Such typological reading discloses the inexhaustible content of the Old Testament; but it must not make us forget that the Old Testament retains its own intrinsic value as Revelation reaffirmed by our Lord himself. Besides, the New Testament has to be read in the light of the Old. Early Christian catechesis made constant use of the Old Testament. As an old saying put it, the New Testament lies hidden in the Old and the Old Testament is unveiled in the New.
228 “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).
202 Jesus himself affirms that God is “the one Lord” whom you must love “with all your heart, and with all your soul, and with all your mind, and with all your strength”. At the same time Jesus gives us to understand that he himself is “the Lord”. To confess that Jesus is Lord is distinctive of Christian faith. This is not contrary to belief in the One God. Nor does believing in the Holy Spirit as “Lord and giver of life” introduce any division into the One God:
We firmly believe and confess without reservation that there is only one true God, eternal infinite (immensus) and unchangeable, incomprehensible, almighty and ineffable, the Father and the Son and the Holy Spirit; three persons indeed, but one essence, substance or nature entirely simple.
575 Many of Jesus’ deeds and words constituted a “sign of contradiction”, but more so for the religious authorities in Jerusalem, whom the Gospel according to John often calls simply “the Jews”, than for the ordinary People of God. To be sure, Christ’s relations with the Pharisees were not exclusively polemical. Some Pharisees warn him of the danger he was courting; Jesus praises some of them, like the scribe of Mark 12:34, and dines several times at their homes. Jesus endorses some of the teachings imparted by this religious elite of God’s people: the resurrection of the dead, certain forms of piety (almsgiving, fasting and prayer), the custom of addressing God as Father, and the centrality of the commandment to love God and neighbor.