This is the mystical meaning behind the, “[If he vows to bring] a small one and brings a large one, he fulfils his obligation”: When one Vows to bring an offering he intends the all-encompassing bringing his entire self near to G-d --(-Minochos 104b), “For what reason is the meal offering different from other offerings in that the term ‘nefesh (lit. a person; soul)’ is stated with regard to it? The Holy One, Blessed be He, said: Whose practice is it to bring a meal offering? It is that of a poor individual; and I will (lit. raise upon him) ascribe him credit as if he offered up his soul (nafsho) in front of Me.” “I will raise upon him” means that he will also have the to empowerment from above, more than possible from his own strength, he will have G-ds, “Raise upon him.” This, through this individual mitzvah he becomes encompassed within the general Mitzvah -the all-encompassing ‘tzavsa’ and oneness of the Jew with G-d. Thus, here is primarily important the content (not just the words) of the offering, that he entirely becomes near, to G-d.
