and distance me from my sins as You have distanced the East from the West.” (1)

He would make this supplication in the opening invocation of the prayer and when rising from bowing.
(Likewise, in the sound report he—peace and blessings be upon him—offered the funeral prayer over a deceased person and said, “O Allah, wash him with water, snow, and ice, and cleanse him of sins just as a white garment is cleansed of dirt.”) (2)

Washing with these substances inevitably cools the one washed, and coldness imparts strength and firmness; indeed, anything that brings delight is described in terms of coolness, (people say) (3) qurratu ʿayn—“coolness of the eye.” Hence tears of joy are cool, whereas tears of grief are hot, because whatever harms the soul causes its sorrow and distress (this arises from inner heat) (4), while whatever pleases it brings about happiness and delight, thereby cooling the inner being (hence the saying, “My heart has cooled”) (5).

Thus the Prophet, peace and blessings be upon him, asked that sins be washed away in a manner that cools the hearts with the greatest possible coolness—namely, through the joy and gladness that removes from him whatever of sin distresses the soul.