Leviticus 7:11

And this is the law of the Sanctified Victims which they may offer before the Lord.

וזאת תורת זבח השלמים, here we are told that although the common denominator between these offerings is that they share the heading sh’lamim inasmuch as these offerings are categorized in the Talmud as קדשים קלים, ”holy things of a minor degree of sanctity,” there are differences, nuances between one type of such קדשים קלים and other types. For instance, if they involve thanksgiving the animals offerings are accompanied by breads, some of which are leavened. Granted that the underlying reason for the need to offer thanks is what our sages call the שאור שבעיסה, “the element of ego in the ‘dough,’” the aspiring human personality, by consisting predominantly of unleavened loaves this element becomes subordinate. [it must be remembered that basically, no other offering consisting of baked goods is allowed to be leavened. The author feels that if a person finds himself in an unexpectedly dangerous situation requiring a miracle to save him, this indicates that had his conduct been beyond reproach he would not first have become exposed to that danger. On a national rather than an individual level, the Purim story is an illustration of what the author means. Ed.] One of the reasons the Torah requires so many individual loaves of bread as part of the Todah sacrifice, is to enable as many people as possible to become aware of someone having been miraculously saved. The period during which these breads can be eaten is the same as the period holy things of the higher order may be eaten, i.e. only one day and one night, not like ordinary sh’lamim which may be eaten two days and one night.

זבח השלמים, “the sacrifice of the peace-offering;” why is it called thus? It is meant to restore peace between us down here and G–d our Father in heaven. This is also described in these terms in Psalms 50 23, when the psalmist says: זובח תודה יכבדנני, “he who sacrifices a thank offering honours Me; the reason the word יכבדנני is spelled with the letter נ repeated, is to hint that G–d will feel honoured both in our world down here and in the heavenly regions.