In that day, he which shall be upon the housetop, and his stuff in the house, let him not come down to take it away: and he that is in the field, let him likewise not return back. He which shall be upon the housetop - See this explained on Matthew 24:17 (note).
Related Commentaries of Luke 17:31
Luke 17:31
31 In that day, he which shall be upon the housetop, and his stuff in the house, let him not come down to take it away: and he that is in the field, let him likewise not return back.