Weeping over the city, Jesus says, "For the days will come on you when your enemies will throw up a barricade against you" (19:43). When did he mean, and what was he speaking of?

Luke gives his words and no more. "When he came near, he saw the city and wept over it" (19:41), "saying, “If you, even you, had known today the things which belong to your peace! But now, they are hidden from your eyes." (19:42). He goes on, "For the days will come on you when your enemies will throw up a barricade against you, surround you, hem you in on every side, and will dash you and your children within you to the ground. They will not leave in you one stone on another, because you didn’t know the time of your visitation." (19:43-44). He names no day or year, and Luke's Gospel tells of no event that keeps these words. These notes name none, bring in no history from outside the Bible, and apply the words to no city, people, war or date.