Parashat Tzav is the twenty-fifth weekly portion in the Torah and the second in the Book of Leviticus (6:1-8:36). Chapters 6 and 7 deal with the laws of the sacrifices, while Chapter 8 tells the story of the weeklong installation ceremony for Aaron and his sons: Nadab, Abihu, Eleazar and Ithamar.
Initially, the first half of the portion might seem like a rehash of the previous week’s laws, detailing the rules for the ola (wholly burnt), mincha (flour), shelamim (peace), chatat (sin) and asham (guilt) offerings. However, if we take a closer look, it becomes clear that the viewpoint is quite different. In Parashat Vayikra, the emphasis is on how the offering is to be brought; in Parashat Tzav, the emphasis is on the aftermath: who consumes what from the sacrifice, when and where. Thus, when it comes to the ola, the Torah stresses that the flame on the Altar must be kept going through the night; the term for this is esh tamid, a continual fire or eternal flame. In commemoration of this, every synagogue has a light above the Ark which is never allowed to go out.
The Torah also tells us that there is a special type of shelamim called the toda, or thanksgiving offering. Psalm 107 famously lists four types of people who must thank God for His salvation: one who crosses the sea, one who crosses the desert, one who survives a health crisis and one who is released from prison. The toda differs from the shelamim in that the latter may be eaten for two days, but the former may be eaten for one day only. In addition, it comes with forty loaves: three types of unleavened bread and one type of leavened bread, ten loaves of each type. Of course, no one person could eat a whole animal and forty loaves of bread in one day; instead, this is meant to be a joyous feast shared with family, friends and the local poor. (The week before Passover — when Parashat Tzav is read in most years — was a particularly popular time to offer the toda.)
To this day, the custom remains to make a toda feast after surviving an ordeal; in addition, the Sages composed a blessing to be said by those who would have brought a toda in Temple times.
The portion from the Prophets begins at the end of the seventh chapter of Jeremiah, with God’s rejection of the burnt-offerings and sacrifices brought by Israel. This stinging rebuke is a strong counterpoint to the laws of the offerings: they are meant to be a means to the end of drawing close to God and accepting His Word. Instead, the sacrifices have become a substitute for faith and good works — a situation which God cannot abide.