Matthew 26:63

‘But Jesus held his peace. And the high priest said to him, “I adjure you by the living God, that you tell us whether you are the Messiah, the Son of God.” '

But Jesus continued to say nothing until eventually the High Priest in desperation, and probably totally exasperated, overstepped the mark and used his power of adjuration. This was the power given to the High Priest as God's earthly representative to adjure a stubborn witness to tell the truth in the Name of God. In response to such a solemn adjuration a reply then had to be given, otherwise there would be an offence against God. However, it was never intended to be used to get a conviction from an accused man's own mouth. But the High Priest in his desperation and exasperation ignored that small distinction and called on Jesus in the Name of the living God to say whether or not He did claim to be ‘the Messiah, the Son of God'. We need not doubt that some such an impression had been given by some of the witnesses. The crucial element in this charge was the claim to be the Son of God. It was not considered blasphemy to claim to be the Messiah, even if it was disapproved of, thus some such charge as a claim to be the Son of God must certainly have been made by someone. Possibly it was partly based on Matthew 22:42, perhaps connected with the parable of the wicked Tenants (Matthew 21:37). Perhaps it even arose from what the evil spirits had cried out (Matthew 8:29).