We certainly must ask: What is “the newness of God” that Pope Francis is referring to?
Cardinal Ratzinger took his segue to answer this from the Rabbi Jacob Neusner in his book “A Rabbi Talks With Jesus”  He comments in his “Jesus of Nazareth” of 2007:
“Let us try to draw out the essential points of this conversation in order to know Jesus and to understand our Jewish brothers better. The central point, it seems to me, is wonderfully revealed in one of the most moving scenes that Neusner presents in his book. In his interior dialogue Neusner has just spent the whole day following Jesus, and now he retires for prayer and Torah study with the Jews of a certain town, in order to discuss with the rabbi of that place—once again he is thinking in terms of contemporaneity across the millennia—all that he has heard. The rabbi cites from the Babylonian Talmud: "Rabbi Simelai expounded: 'Six hundred and thirteen commandments were given to Moses, three hundred and sixty-five negative ones, corresponding to the number of the days of the solar year, and two hundred forty-eight positive commandments, corresponding to the parts of man's body.
"'David came and reduced them to eleven.. . .
'"Isaiah came and reduced them to six. . . .
'"Isaiah again came and reduced them to two. . . .
'"Habakkuk further came and based them on one, as it is said: "But the righteous shall live by his faith'" (Hab 2:4)."
Neusner then continues his book with the following dialogue: “’So,’ the master says, 'is this what the sage, Jesus, had to say?'
"I: 'Not exactly, but close.'
"He: 'What did he leave out?'
"He: 'Then what did he add?'
"I: 'Himself’ (pp. 107-108).”
This is the central point where the believing Jew Neusner experiences alarm at Jesus' message, and this is the central reason why he does not wish to follow Jesus, but remains with the "eternal Israel": the cen-trality of Jesus' "I" in his message, which gives everything a new direction. At this point Neusner cites as evidence of this "addition" Jesus' words to the rich young man: "If you would be perfect, go, sell all you have and come, follow me" (cf. Mt 19:21; Neusner, p. 109 [emphasis added]). Perfection, the state of being holy as God is holy (cf. Lev 19:2, 11:44), as demanded by the Torah, now consists in following Jesus.
It is only with great respect and reverence that Neusner addresses this mysterious identification of Jesus and God that is found in the discourses of the Sermon on the Mount. Nonetheless, his analysis shows that this is the point where Jesus' message diverges fundamentally from the faith of the "eternal Israel." Neusner demonstrates this after investigating Jesus' attitude toward three fundamental commandments: the fourth commandment (the commandment to love one's parents), the third commandment (to keep holy the Sabbath), and, finally, the commandment to be holy as God is holy (which we touched upon just a moment ago). Neusner comes to the disturbing conclusion that Jesus is evidently trying to persuade him to cease following these three fundamental commandments of God and to adhere to Jesus instead” (Blogger’s emphasis).
The “newness” of the revelation of Jesus Christ is no commandment, moral principle or law, but Himself: The “I Am” of Jn. 8, 24, 28, 58; the “It is I” of Luke 24, 37 after the Resurrection. The “I” of Christ is the novelty of God in time and space.