יחזקאל לא:טו פירוש: רש״י

On the day he descended into the Grave When I humbled the king of Assyria into the hands of his enemy.

I caused mourning [I caused] many mourners who relied on him [to mourn] over him.

I covered the deep on his account I covered the deep because of him, for it was accustomed to water him and cause his growth, as Scripture stated above (verse 4): “the deep made it grow tall.” That day, I covered it so that it should not ascend and extinguish his fire. i.e., I weakened his aids.