Leviticus 23:1 - 44
NKJV - 1 And the LORD spoke to Moses, saying. 2 Speak to the children of Israel, and say to them: 'The feasts of the LORD, which you shall proclaim to be holy convocations, these are My feasts.
*Excerpted from my commentary to the book of Leviticus, available on eBible.com at http://ebible.com/plans/landing/626 The chapter passage you referenced only briefly mentions fire offerings (Lev 23:18, 37), however, fire offerings were very common in ancient Isra'el and as such, the first chapter of the book of Leviticus outlines the logistics for them: “The Lord called Moses and spoke to him from the tent of meeting, saying, “Speak to the people of Israel and say to them, When any one of you brings an offering to the Lord, you shall bring your offering of livestock from the herd or from the flock. “If his offering is a burnt offering from the herd, he shall offer a male without blemish. He shall bring it to the entrance of the tent of meeting, that he may be accepted before the Lord. He shall lay his hand on the head of the burnt offering, and it shall be accepted for him to make atonement for him. Then he shall kill the bull before the Lord, and Aaron's sons the priests shall bring the blood and throw the blood against the sides of the altar that is at the entrance of the tent of meeting. Then he shall flay the burnt offering and cut it into pieces, and the sons of Aaron the priest shall put fire on the altar and arrange wood on the fire. And Aaron's sons the priests shall arrange the pieces, the head, and the fat, on the wood that is on the fire on the altar; but its entrails and its legs he shall wash with water. And the priest shall burn all of it on the altar, as a burnt offering, a food offering with a pleasing aroma to the LORD” (Lev 1:1-9, ESV). There are five types of offerings introduced in the opening pages of Leviticus: 'Olah (Burnt Offering) – Lev. 1:1-17 Minchah (Grain Offering) – Lev. 2:1-16 Sh’lamim (Peace Offering) – Lev. 3:1-17 Chata’at (Sin Offering) – Lev. 4:1-35; 5:1-13 ‘Asham (Guilt Offering) – Lev. 5:14-26 Important by comparison is that the first three could easily be considered “freewill offerings,” brought before God by anyone at various times in the life of anyone in the community, and they did not address atonement for ritual sins. This means, since they did not atone for sins of the flesh (the kind that stained the Sanctuary of God), they could essentially be brought as an expression of the thankfulness of an individual. The last two, however, were required to make restitution for various sins in the flesh (ritual sins). Such offerings (chata’at and ’asham) are referred to as “expiatory.” In conclusion, we know that our God was pleased with worshippers bringing burnt offerings, because the burnt offering (fire offering) was completely burnt up on the altar (completely offered to God, with nothing eaten by the worshipper) and the result was said to be “re’ach nichoach la’ADONAI” (Hebrew=רֵֽיחַ־נִיחֹוחַ לַֽיהוָֽה), that is, “a pleasing aroma to the LORD).