Albert Barnes Commentary Mark 13:11

"And when they lead you [to judgment], and deliver you up, be not anxious beforehand what ye shall speak: but whatsoever shall be given you in that hour, that speak ye; for it is not ye that speak, but the Holy Spirit." — Mark 13:11 (ASV)

Neither do you premeditate. Do not think beforehand, or prepare an answer. You do not know what the accusations will be, and God will furnish you with a reply that will be adapted to the occasion.

Not you that speak, but the Holy Ghost. This is a full promise that they would be inspired; and consequently their defenses recorded in the Acts of the Apostles are the words of the Holy Ghost. There could be no more explicit promise that they would be under infallible guidance; and we are not left to doubt that they were taught by God.

At the same time, this was a most desirable and gracious aid. They were illiterate, unknown, and without power. They were unfit in themselves to make the important statements of religion that were required. But God gave them power, and they spoke with a wisdom, fearlessness, pungency, and ability that no other men have ever manifested—full proof that these illiterate fishermen were under the influence of the Holy Ghost.