In the commentary of Toras Kohanim on the Torah portion of Vayikra , our Sages note that a gift of wood for use upon the altar may constitute a valid sacrificial offering.1 How can a mere adjunct to the actual offerings constitute a valid offering in itself?

The Ramban explains the significance of offerings in the following manner:2 The person who brings an animal sacrifice must realize that all those things being done to the animal should by right have been done to him. It is only because of G‑d’s mercy that an animal is substituted.

Thus, the intent of one bringing an animal sacrifice should be to offer himself to G‑d. This also serves to explain why every sacrifice had to be consumed together with the wood of the altar:

There are various types of sacrifices, each possessing its own laws as to the manner in which it is to be offered. According to the Ramban , we may understand the differences in the laws according to the effect the particular offering has upon the individual who brings it. This depends, of course, on the reason the offering is brought — whether it is an expiation offering, a free-will offering, etc.

On the other hand, the essence of every sacrifice is the offering of the person himself ; the person must be prepared to dedicate himself entirely to G‑d. It is only then that each form of offering fulfills its purpose.

That all offerings share this attribute is symbolized by the wood that is consumed together with every sacrifice: the wood provides the constant subtext of every offering — that the person offers himself to G‑d.

The Torah tells us that “Man is a tree of the field.”3 Man’s offering of himself to G‑d is thus expressed by means of wood. One of the differences between man’s “general offering” that finds expression in the consumption of wood upon the altar, and the “particular offering” of man’s individual powers (symbolized by the various sacrifices) is the following:

When a person offers a particular part of himself, he cannot free himself entirely of his ego, for his self-abnegation and devotion to G‑d refer only to this particular part of himself. The remaining components in every personality conceal and hinder a person’s selfless devotion to G‑d.

When a person realizes that, regardless of the particular nature of his sacrifice, he is offering himself totally to G‑d, there is nothing left within him to act as a barrier. The person then can dedicate himself in a manner that transcends intellect or emotion — even holy intellect and emotion.4

Based on Likkutei Sichos Vol. XXII pp. 7-12.