John Gill Commentary Luke 17:31

"In that day, he that shall be on the housetop, and his goods in the house, let him not go down to take them away: and let him that is in the field likewise not return back." — Luke 17:31 (ASV)

In that day, he which shall be upon the housetop
Either for diversion or devotion, when he shall hear that the Roman armies are approaching to Jerusalem, to besiege it:

and his stuff in the house ;
or "his vessels", his goods and furniture; or his utensils, and instruments of trade and business:

let him not come down ;
the inner way of the house, from the top:

to take it away ;
with him in his flight, but let him descend by the steps, or ladder, on the outside of the house, and make his escape directly to Pella, or the mountains:

and he that is in the field ;
at work, and has laid down his clothes in some certain part of the field, or at home:

let him likewise not return back ;
to fetch them, but make the best of his way as he is; (See Gill on Matthew 24:17) and (See Gill on Matthew 24:18).