John Gill

Let him which is on the housetop,.... Who should be there either for his devotion or recreation; for the houses of the Jews were built with flat roofs and battlements about them, which they made use of both for diversion and pleasure, and for private meditation and prayer, for social conversation, and sometimes for public preaching; see Mat 10:27 not come down to take anything out of his house: that is, let him not come down in the inner way, but by the stairs, or ladder, on the outside of the house, which was usual. They had two ways of going out of, and into their houses; the one they call (d), , "the way of the doors"; the other, , "the way of the roof": upon which the gloss is, "to go up on the outside, , "by way" or "means" of a ladder, fixed at the entrance of the door of the upper room, and from thence he goes down into the house by a ladder;'' and in the same way they could come out; see Mar 2:4 and let him not go into his house to take any of his goods, or money, or food along with him necessary for his sustenance in his flight; lest, whilst he is busy in taking care of these, he loses his life, or, at least, the opportunity of making his escape; so sudden is this desolation represented to be. (d) T. Bab. Bava Metzia, fol. 117. 1.