Adam Clarke on Matthew 26:63

I adjure thee by the living God - I put thee to thy oath. To this solemn adjuration Christ immediately replies, because he is now called on, in the name of God, to bear another testimony to the truth. The authority of God in the most worthless magistrate should be properly respected. However necessary our Lord saw it to be silent, when the accusations were frivolous, and the evidence contradictory, he felt no disposition to continue this silence, when questioned concerning a truth, for which he came into the world to shed his blood.