In ancient times, sacrifice, not prayer, was the main mode of “Jewish” or “Israelite” worship. A “sacrifice” was called a “korban:” something “brought near” – i.e. to the Mishkan/Temple, or to the altar-fire, or figuratively, to G-d’s own Presence.

The study of the sacrifices is complicated – even on the “pshat,” or literal level of Torah. There are so many details; so many things that distinguish one type of sacrifice from another. Nor are the details themselves always clear without reference to even a simple commentary.

The fundamental type of korban, or sacrifice, was the “Olah” – the “burnt offering.” A bull or male sheep or goat was slain in the quickest, gentlest way possible. Its blood was sprinkled around the altar. It was then flayed and burnt virtually entirely in the altar fire. For those who couldn’t afford an animal, a bird or even some grain was no less acceptable (in the Midrash, even preferable, at times). Certain “olot” (plural of “olah”) were required; others were voluntary. The “olah” was accompanied by offerings of grain or meal and wine.

There was another class of sacrifices called the “Sh’lamim” – sometimes called “Peace Offerings” or “Well-being Offerings.” In these, the slain animal could be male or female. Its blood was sprinkled, but only part of the animal was burnt on the altar. The remainder was shared between the kohen (priest) and the “owner” or offerer, who could then share it with friends, neighbors, community, etc.

Within the overall class of “Sh’lamim” was the sub-category of the “(Korban) Todah” – the voluntary “Thank Offering” or “Thanksgiving Offering.”

How important was the Korban Todah?

The rabbis taught that in the future, all sacrifices would cease except the Todah! There would be no more sin, so there would be no further need for atonement. There would be more sense of separation from G-d, so there would be no need for the “rapprochement” that the Korban Olah and other sacrifices afforded. But there will always be a need for gratitude, even in an era of universal enlightenment. In fact, one of the features of the future world will be that we’ll no longer ascribe the things that happen to us to anything or any being other than G-d. All will be recognized as having a Divine, Good Source.

The rabbis say something parallel about prayer: In the future, all prayers will cease except prayers of gratitude.

What are “prayers of gratitude?” They’re very common in Jewish practice, actually. Every brachah – blessing – we say is, in essense, a “Korban Todah.” The rabbis might have specified different blessings for different foods and different occasions (returning from a long journey, for example), but underlying them all is the same expression of gratitude that was originally made through the Korban Todah. It’s clear, in fact, that the rabbis wanted to weave this gratitude into our daily experience of life.

The American holiday of “Thanksgiving” (and, indirectly, the Canadian holiday, too) has roots in the “Korban Todah.” The Puritans saw in it (and in some of the rabbinic interpretations of it) a model of how to thank G-d for what had happened to and for them in their journey to America.
(See: http://www.jewishideasdaily.com/1011/features/thanksgiving-a-jewish-holiday-after-all/.)

There have been debates about whether Jews should observe the American holiday of Thanksgiving. This question isn’t unique to Jews, either: Jehovah’s Witnesses and others also abstain from holidays that don’t have a clearly Biblical basis.

That debate aside, we can learn much from the American holiday of Thanksgiving about the feelings originally associated with the Korban Todah.