Church Fathers on Luke 17:36

Our Lord had just before said, that he who is in the field must not return back; and lest this should seem to have been spoken of those only who would openly return from the field, that is, who would publicly deny their Lord, He goes on to show, that there are some who, while seeming to turn their face forward, are yet in their heart looking behind.

He rightly says, night, for Antichrist is the hour of darkness, because he pours a dark cloud over the minds of men while he declares himself to be Christ. But Christ as lightning shines brightly, that we may be able to see in that night the glory of the resurrection.

Or He says, in that night, meaning in that tribulation.