Mark 15:33

And when the sixth hour was come i. e. 12 o'clock. The most mysterious period of the Passion was rapidly drawing near, when the Lord of life was about to yield up His spirit and taste of death. At this hour nature herself began to evince her sympathy with Him Whom man rejected. The clearness of the Syrian noontide was obscured, and darkness deepened over the guilty city. It is impossible to explain the origin of this darkness. The Passover moon was then at the full, so that it could not have been an eclipse. Probably it was some supernatural derangement of the terrestrial atmosphere. The Pharisees had often asked for a "sign from heaven." Now one was granted them.

until the ninth hour i. e. till 3 o'clock. A veil hides from us the incidents of these three hours, and all the details of what our Lord, shrouded in the supernatural gloom, underwent "for us men and for our salvation."