While weeping over Jerusalem, Jesus describes enemies surrounding the city and casting up an embankment against it. These are not vague metaphors for difficulty; they belong to the technology and terror of ancient siege warfare.
Luke then speaks of devastating destruction in which stones are thrown down.
Fortified cities were attacked by encirclement, siege works, earthworks, ramps, artillery, assault, starvation, and blockade. The precise tactics varied with terrain and circumstances. Jerusalem's defenses made a Roman siege a major military undertaking.
In AD 70 Roman forces under Titus captured Jerusalem after a brutal siege and destroyed the Temple. Luke's language corresponds naturally to the realities of siege warfare and to the catastrophe that overtook the city.
The military background prevents Jesus' lament from sounding like generalized religious rhetoric. He envisions civilians trapped inside a surrounded city and monumental structures reduced to ruin.
That makes his tears over Jerusalem integral to the warning. Judgment is described not abstractly but in the human and physical terms of war, siege, and the destruction of a beloved city.