Adam Clarke on Luke 19:43

Cast a trench about thee - This was literally fulfilled when this city was besieged by Titus. Josephus gives a very particular account of the building of this wall, which he says was effected in three days, though it was not less than thirty-nine furlongs in circumference; and that, when this wall and trench were completed, the Jews were so enclosed on every side that no person could escape out of the city, and no provision could be brought in, so that they were reduced to the most terrible distress by the famine which ensued. The whole account is well worth the reader's attention. See Josephus, War, book v. chap. xxii. sec. 1, 2, 3.