Leviticus 16 - The Day of the Atonement Chapter. This day is the most important day in the Hebrew calendar. It was the day when "atonement" was made for the sins of all the people throughout the previous year. A sacrifice had to be made by the priest who then would offer the necessary sacrifices to God on behalf of everyone else. Two goats were involved and you'll see how the term "scape-goat" had its origin. This also was the one day out of the year when the high priest could actually come into the Holy of Holies to sprinkle blood on the Ark of the Covenant. But note, the priest had to come in with a very smoky incense offering ahead of him. That smoke was to hinder his eyes from seeing too much. Praise the Lord that in heaven we won't need any smoke to hinder our vision of God!
Leviticus 17 - Sacrifices that the people of Israel wished to present to the Lord must be done only at the Tabernacle. A further warning is given against eating blood. God places high priority on that which is the "life of the flesh" - blood. That is why the shed blood of Christ is so important in the eyes of God. Our access to God is made possible because Jesus shed His blood on our behalf.
Leviticus 18 - Sexual purity is the subject of this chapter. Back in the culture in ancient times too many people were despising the sanctity of sex in incestuous ways. God meant sex to be a personal and intimate way a married couple could enjoy their relationship together. The devil has taken this beautiful display of affection and distorted it into a careless pleasure-only activity between people who should never have such relationships. God expects His people to live holy lives.