God demands great detail and observance about things offered to Him.
1 Peter 2:5 you also, like living stones, are being built into a spiritual house to be a holy priesthood, offering spiritual sacrifices acceptable to God through Jesus Christ.
The offerings mentioned in Leviticus and elsewhere in the Old Testament have spiritual significance for us. How will I know what God wants if I do not read these things? We are told that our Saviour Jesus was and is the meaning of all the imagery of the Old Testament – indeed He can be found everywhere in the Old Testament. The offerings describe in detail what Jesus achieved through His life and death and resurrection. The sacrifices, the ceremonies, the Tabernacle, the Priesthood, all hold beautiful pictures (or shadows) of the One who would come and fulfil it all!
Hebrews 9:11 But when Christ came as high priest of the good things that are now already here, he went through the greater and more perfect tabernacle that is not made with human hands, that is to say, is not a part of this creation.
In the simplest of words – the offerings had to be the best standard possible in order to portray that Jesus, in offering Himself, was and is the best of all! This is the major theme of the letter to the Hebrews where you can read the word “better” over and over again. Jesus is better than all the rest!
So, when God introduces the Law of the Offerings (sacrifices) He begins with the things closest to “the best”. The offering had to be the best young male in the herd [read Leviticus chapter 1]. It had to be perfectly formed and without any blemish on or under the skin. It had to be killed, flayed, so that the skin could be removed, and then the body was cut in pieces. Every bit was set in order over the fire. Legs and inward parts had to be washed in running water. Too many pictures of sacrifices miss all this and show a whole animal on an altar with blood trickling out. The blood had been drained and spread around providing ground sanctified by the blood. Every part of the offering was acceptable to God. Everything about Jesus – His daily life, His inward being and secrets of His soul, His thoughts and words and deeds were all acceptable to God. They smelled good
Now, these burnt offerings are described in a kind of hierarchy. Next comes a sheep or goat. Then for those without such wealth, they could offer a pigeon. Please see and note that all of these whole burnt offerings were acceptable to God and smelled good!
We learn from this that, no matter how long you have been a Christian, no matter what your education or ability, no matter how good your memory or ability with language; your worship is acceptable to God – as long as it centres on what you know about Jesus and is the best you can bring.
This offering is not really about confessing sins but is about being acceptable to God. The animal is accepted in the place of the offerer.