Then the high priest rent his clothes - The Jews were accustomed to rend their clothes as a token of grief. This was done often as a matter of form, and consisted in tearing a particular part of the garment reserved for this purpose. It was not lawful for the high priest to rip his clothes, Leviticus 10:6; Leviticus 21:10. By that was probably intended the robes of his priestly office. The garment which he now tore was probably his ordinary garment, or the garments which he wore as president of the Sanhedrin - not those in which he officiated as high priest in the things of religion. This was done on this occasion to denote the great grief of the high priest that so great a sin as blasphemy had been committed in his presence.
He hath spoken blasphemy - That is, he has, under oath, arrogated to himself what belongs to God. In asserting that he is the Son of God, and therefore equal in dignity with the Father, and that he would yet sit at his right hand, he has claimed what belongs to no man, and what is therefore an invasion of the divine prerogative. If he had not been the Messiah, the charge would have been true; but the question was whether he had not given evidence that he was the Messiah, and that therefore his claims were just. This point - the only proper point of inquiry - they never examined. They assumed that he was an impostor, and that point being assumed, everything like a pretension to being the Messiah was, in their view, proof that he deserved to die.