A typical case is the proclamation of the Kingdom of God "which is at the heart of the historic Jesus’ teachings" whereas in Paul "a transposition can be noticed: the theme of God’s reward is transformed in Christology." Nevertheless, the same requirements set by Jesus to enter the Kingdom of God are exactly valid for Paul concerning the justification by faith," the Pope said. For both, an attitude of great humility and availability, free of presumptuousness, is a requirement to welcome God’s grace." Speaking about Jesus’ invocation "Abba Father," Benedict XVI pointed out that this was "a familiar expression used by children. It was unconceivable that a Jew could use it to address their father." Yet this expression, in St. Paul’s Letter to the Romans, is surprisingly used by baptised people." Last, the saving dimension of Christ’s death as "ransom, redemption, liberation and reconciliation" is the "core of St. Paul’s theology." ” ” ” ” ” “