Mark 13:18-23 Pray that this will not take place in winter, because those will days of distress unequaled from the beginning, when God created the world, until now - and never to be equaled again. If the Lord had not cut short those days, no one would survive. But for the sake of the elect, whom he has chosen, he has shortened them. At that time if anyone says to you, 'Look, here is the Christ!' or 'Look, there he is!' do not believe it. For false Christs and false prophets will appear and perform signs and miracles to deceive the elect - if that were possible. So be on your guard; I have told you everything ahead of time.

(Note: I copied advance, the verses Mark 17:21-23 so we can understand very well. Thanks.)