Blown over by a leaf – B’chukkotai
The curses of the Tochechah are quite horrendous. There are big threats and small threats. One of the apparently small ones is that even a leaf can knock you over (kol aleh niddaf; Lev. 26:36).
You have to be very fragile for such a thing to be possible, but the Torah is uttering a grave warning: if you disobey the Divine law you will lose all your physical strength and moral stamina and will have no power of resistance.
Rashi gives the verse an extra dimension. If you hear the rustling of the wind you will think a powerful army is after you and you will only want to run away.
Never mind that it’s only the wind in the leaves; you’ll be so faint-hearted and jumpy that your imagination will play tricks with you.