'On that Day' in the Bible

I tell you, the people of Sodom will be shown more leniency on that day [i.e., the day of judgment] than that town will receive.

On that day, the person who is on a housetop [Note: This was a flat area where people retired for rest, prayer, etc., with its stairway on the outside], whose belongings are [still] in his house, is not to go down and [attempt to] take any of them away. And the person who is in a field [i.e., doing farm work], also is not to return [to his house].

But you should be alert at all times, offering earnest prayers, so that you will be strong enough to escape all these things that will happen, and to appear [acceptable] in front of the Son of man [on that day]."