The Alter Rebbe explains there that the illumination from the supernal will that shines within the devotion that accompanies an action is likened to a “soul,” relative to the illumination that shines in the action itself, which is likened to a “body” or garment for the soul. The difference is thus only in the degree of contraction or emanation of this radiance.

From the above, it is clear that even the garments for the soul that are created from the devotion and feeling that accompany Torah and prayer also result only from the radiance of the supernal will, which is the supernal keter.