Musar sobre Números 28:8

To explain the matter in a way that our ears can understand: The soul, which is called a “small world,” is sustained only by smell. Thus the Sages comment, “What is there that the soul benefits from but not the body? It is smell” (Berachos 43b). In the same way, the large worlds, both lower and upper, are also sustained by smell alone. Thus for as long as the Temple stood, Israel offered up sacrifices there and while reflecting on all the esoteric “unifications” connected with the sacrifice as well on as the holy Divine Names deriving from the verse, “a fire-offering, a sweet smell to Hashem” (Bamidbar 28:8). In this way the sacrifice would awaken Heaven’s favor and all the worlds would be united in a single bond. Thus the word korban — “sacrifice” — derives from the word keiruv — “drawing close.” Nowadays the exhalation of a person’s breath in prayer takes the place of the sacrifices, as does Torah study. For instance, whoever engages in the study of the burnt sacrifices is credited as if he offered one (Menachos 100a). In the same way, the breath that is exhaled in prayer on a fast day is also comparable to the fragrance of the sacrifices.