Commentaire sur Joël 2:2

like the dawn, spread over the mountains—The increasing locusts and the shearing locusts are spread over the mountains as the dawn is spread over the entire world.

1. and it mentions the day of the destructions that it will be a day of darkness and dense clouds, smoke and gloom. These descriptions all apply to the destruction of the first Temple and the troubles that came along with. And on this Ivoy (3:5) says about the day of his birth "may darkness and gloom claim it and a cloud lie on it". And maybe it is a hint to the day that is decreed for our troubles that is the 9th of Av. Because that is the day of Gd that he put aside to take vengence on His nation and it was darkness and gloom for the generation who was in the desert because on that day the decrees of the spies took place. And it was a day of clouds and smoke when the Temple was destroyed. And it is say it is spreaking on the mountains meaning that it is like there was no light in the world except the darkness and that was spreading on the mountains. The word in the pasuk "shachar" is from the root of the word "black" and therefore the daybreak is called "shachar" because the light has not yet started to spread on the world. And the meaning is the darkness hints to a great multitude of a nation that Nevuchad nezer brought to Jerusalem that was great in number and mighty in stregnth and there was never before like it in the world and never again afterwards for gerenations. This means that from the time the world was created, no nation had ever gone to war with such a great and mighty army like him and afterwards this will never be for generations. even the army led by Titus to destoruy the second Temple was much larger than Nevud Nezers and therefore it says "for generations" since Titus's army was many generations later after 500 years.

the like of which has never been—that all these species should come one after the other, but the species of arbeh alone did not equal that of Egypt, concerning which it is stated: (Exodus 10:14) “And after it there shall not be so.”