In the middle of the week 1 the yetzer hara will sometimes over-power you, by making it seem to you that your fasting is very difficult for you, and saying that you are unable to bear it. 2 Understand that the yetzer [hara] is envious of you, lest you attain a [higher] level. 3 That is why he instigates so much against you.

If you are wise and over-power the yetzer [hara], you will effect something great on high. Thus it is said in the Zohar (II:128b and 184a), “The glory of the Holy One, blessed is He, is increased when that sitra achara (other side; the side of evil) is subdued for the sake of His service.” The yetzer [hara] greatly desires to prevent you from fasting; but as you over-power him, the sitra achara is very much subdued. 4

The yetzer hara is sometimes allowed to cause you great pain. This happens to test you whether you will persist and over-power the yetzer hara. [If you do so, you will note] afterwards, at the conclusion of the fast, that you no longer sense the great pain you felt at the time.

Beseech the mercies of the Creator, blessed be He, to strengthen your eyes so that they will not be affected adversely by your fasting. 5