If the Law and the Jerusalem Temple could be occasions of opposition to Jesus by Israel’s religious authorities, his role in the redemption of sins, the divine work par excellence, was the true stumbling-block for them.
Jesus scandalized the Pharisees by eating with tax collectors and sinners as familiarly as with themselves. Against those among them “who trusted in themselves that they were righteous and despised others”, Jesus affirmed: “I have not come to call the righteous, but sinners to repentance.” He went further by proclaiming before the Pharisees that, since sin is universal, those who pretend not to need salvation are blind to themselves.
Jesus gave scandal above all when he identified his merciful conduct toward sinners with God’s own attitude toward them. He went so far as to hint that by sharing the table of sinners he was admitting them to the messianic banquet. But it was most especially by forgiving sins that Jesus placed the religious authorities of Israel on the horns of a dilemma. Were they not entitled to demand in consternation, “Who can forgive sins but God alone?” By forgiving sins Jesus either is blaspheming as a man who made himself God’s equal, or is speaking the truth and his person really does make present and reveal God’s name.
Only the divine identity of Jesus’ person can justify so absolute a claim as “He who is not with me is against me”; and his saying that there was in him “something greater than Jonah,. . . greater than Solomon”, something “greater than the Temple”; his reminder that David had called the Messiah his Lord, and his affirmations, “Before Abraham was, I AM”, and even “I and the Father are one.”
Jesus asked the religious authorities of Jerusalem to believe in him because of the Father’s works which he accomplished. But such an act of faith must go through a mysterious death to self, for a new “birth from above” under the influence of divine grace. Such a demand for conversion in the face of so surprising a fulfilment of the promises allows one to understand the Sanhedrin’s tragic misunderstanding of Jesus: they judged that he deserved the death sentence as a blasphemer. The members of the Sanhedrin were thus acting at the same time out of “ignorance” and the “hardness” of their “unbelief”.
From the Catechism of the Catholic Church 587-591