Theophylact of Ohrid
Catena Aurea · Markusevangelium 13
And then if any man shall say to you, Lo, here is Christ; or, lo, he is there; believe him not: For false Christs and false prophets shall rise, and shall shew signs and wonders, to seduce, if it were possible, even the elect. But take ye heed: behold, I have foretold you all things. But in those days, after that tribulation, the sun shall be darkened, and the moon shall not give her light, And the stars of heaven shall fall, and the powers that are in heaven shall be shaken. And then shall they see the Son of man coming in the clouds with great power and glory. And then shall he send his angels, and shall gather together his elect from the four winds, from the uttermost part of the earth to the uttermost part of heaven.
After that the Lord had finished all that concerned Jerusalem, He now speaks of the coming of Antichrist, saying, Then if any man shall say to you, Lo, here is Christ; or, lo, he is there; believe him not. But when He says, then, think not that it means immediately after these things are fulfilled about Jerusalem; as Matthew also says after the birth of Christ, In those days came John the Baptist; (Matt. 3:1) does he mean immediately after the birth of Christ? No, but he speaks indefinitely and without precision. So also here, then may be taken to mean not when Jerusalem shall be made desolate, but about the time of the coming of Antichrist. It goes on: For false Christs and false prophets shall arise, and shall shew signs and wonders, to seduce, if it were possible, even the elect. For many shall take upon them the name of Christ, so as to seduce even the faithful.