Luke 22:67-71 (ESV):
"If you are the Christ, tell us." But he said to them, "If I tell you, you will not believe,and if I ask you, you will not answer.But from now on the Son of Man shall be seated at the right hand of the power of God." So they all said, "Are you the Son of God, then?" And he said to them, "You say that I am." Then they said, "What further testimony do we need? We have heard it ourselves from his own lips."In Luke 22:67-71, The Jews asked Jesus "Are You the Christ?" Jesus told them yes. They did not accuse Him of blasphemy for claiming to The Messiah!!!!!!
They next asked Him "Are You the Son of God, then?" and when Jesus said "Yes," then they immediately accused Jesus of blasphemy and condemned Him as worthy of DEATH. Why did they do that? John 19:7 explains:
John 19:7 (ESV): The Jews answered him, "We have a law, and according to that law he ought to die because he has made himself the Son of God"
The Jews did not condemn Jesus for claiming to be the Messiah, but they DID condemn Him for claiming to be The Son of God!
Jesus used "Son of Man" as a title while on earth. It meant that Jesus was truly a Man, that He was fully Human. It was used the same way that the phrase "sons of the prophets" was used in the Old Testament. "Sons of the prophets" meant "of the order of the prophets."
So also, when Jesus used the title "The Son of God" it had the same meaning. He meant that He was "of the order of God," that He was fully Divine, and truly God. That is why the Pharisees reacted the way they did in John Chapter 5:
John 5:16-18 (ESV):
And this was why the Jews were persecuting Jesus, because he was doing these things on the Sabbath. But Jesus answered them, "My Father is working until now, and I am working." This was why the Jews were seeking all the more to kill him, because not only was he breaking the Sabbath, but he was even calling God his own Father,making himself equal with God.Jesus claimed that He was the UNIQUE Son of God, and that He had equal rights and authority with The Father to work on the Sabbath.