en_tn_condensed/luk/17/31.md

let him who is on the housetop not go down

"whoever is on the housetop must not go down" or "if anyone is on his housetop, he must not go down."

on the housetop

Their housetops were flat, so people could walk or sit on them.

his goods

"his possessions" or "his things"

let him who is in the field not return

"whoever is in the field must not go back to his house." They must not go back to their house to get anything. They must flee quickly.