פירוש על מלכים ב 19:26

Their inhabitants were short of strength. Those whom I weakened before you,¹⁶I.e., it is a Divine gift for which Sancheiriv could claim no credit. and the might is not yours.¹⁷The nations that Sancheiriv conquered had already been condemned to punishment and destruction. You are not mighty, rather they are weak.¹⁸In Tehilim 129:6 the verse states” … like the grass on rooftops which even before it is plucked, withers.”

They were broken

Like grass of the rooftops. Which dries quickly.¹⁹Alternatively, grass is unable to move and defend itself from being cut.—Ralbag

W

And wind blast before [becoming] standing grain. Like blasted stalks of grain, before they hardened to become standing grain.