Tanya for the 4th of Kislev ד' כסלו

Torah study and prayer can only grasp G-d's existence, but with the fulfillment of the commandments we are able to grasp G-d's essence. This is because of the pattern of descent of G-dly energy into this physical lower world. Contained in the lowest manifestation of physicality is an emanation of G-dly energy that is only tapped into through physical action.