10 The true Christ, the Only-begotten Son of God, comes no more from the earth. If any come making false shows in the wilderness, go not forth; if they say, Lo, here is the Christ, Lo, there, believe it not. Look no longer downwards and to the earth; for the Lord descends from heaven; not alone as before, but with many, escorted by tens of thousands of Angels; nor secretly as the dew on the fleece; but shining forth openly as the lightning. For He has said Himself, As the lightning comes out of the east, and shines even unto the west, so shall also the coming of the Son of Man be; and again, And they shall see the Son of Man coming upon the clouds with power and great glory, and He shall send forth His Angels with a great trumpet; and the rest.
Source: Catechetical Lectures (New Advent)