Matthew Poole and continuators on Lamentations 4:12

12 The kings of the earth, and all the inhabitants of the world would not have believed, that the adversary and the enemy should have entred into the gates of Jerusalem .

Ierusalem was so naturally and artificially fortified, and so favoured by God; and taken notice of as a place which the Lord cared for, and watched over, that it could not have entred into the thoughts of any of those that were Enemies to it, that they should ever have been able to make themselves masters of it.