Then he shall offer the second for a burnt offering according to the rule. And the priest shall make atonement for him for the sin that he has committed, and he shall be forgiven.
God is holy and to worship Him in His holiness requires that we take our own lack of holiness very seriously. God must atone for our sins. And Leviticus has a heavy emphasis on God's holiness, human sinfulness, and the way in which God provided for atonement for sin via sacrifices through the priestly system under Aaron and Moses. The intense regulations for sacrifices emphasize the degree of sin's offense against God. The ways in which the sacrifices could atone for anyone regardless of economic ability (they could bring a bull to be sacrificed, down through a list of smaller animals, or simply fine flour if they had no livestock), emphasizes the grace of God in atoning for sin.
Yet each of these levitical sacrifices was only temporary. Repeated sacrifices had to be made so that sin could be atoned. The priests were constantly bloodying the altar with the sacrifices of repentant sinners. It was a brutal and demanding reminder of the pervasive depth of sin. It kept Israel always aware of the need for God's wrath to turned as the price of sin was constantly being paid in sacrifices that brought atoning mercy to the nation.
God was gracious to provide the means through priests, altars, and sacrifices for His people to receive mercy. The near constant stream of sacrifices kept humility and confession visibly in front of the people. And the atonement at the altar kept forgiveness at great personal cost always on their minds. Looking back on Leviticus now through the gospel, I am so grateful Jesus made complete atonement at the greatest cost so my sin is forgiven completely, once for all forever.