Charles Ellicott Commentary Matthew 26:65

"Then the high priest rent his garments, saying, He hath spoken blasphemy: what further need have we of witnesses? behold, now ye have heard the blasphemy:" — Matthew 26:65 (ASV)

Then the high priest rent his clothes — This act was a formal sign of condemnation, much like an English judge putting on the black cap. In a Jewish trial for blasphemy, the judges were required to tear their clothes in two when the blasphemous words were spoken, and the torn garments were never to be mended.

The same act appears in Acts 14:14, where it expresses the impulsive horror of Paul and Barnabas. This was just as it had been long ago when Eliakim tore his clothes upon hearing the blasphemies of Rabshakeh (2 Kings 18:37).

A comparison of the Greek word used here and in Mark 14:63 shows that the tearing included the tunic, or undergarment, as well as the cloak.