Daniel 12:1

And at that (a) time shall Michael stand up, the great prince which standeth for the children of thy people: and there shall be a time of trouble, such as never was since there was a nation [even] to that same time: and at that time thy people shall be delivered, every one that shall be found written in the book.

(a) The angel here notes two things: first that the Church will be in great affliction and trouble at Christ's coming, and next that God will send his angel to deliver it, whom he here calls Michael, meaning Christ, who is proclaimed by the preaching of the Gospel.