v1: The message of mercy; access to God was still possible, although still on God's terms.
v2-3: Even the High Priest could not enter the Most Holy Place at simply any time. He had to come at a specific time, and with a sacrifice. This was the Day of Atonement (Yom Kippur).
v4: The High Priest had to wear holy linen garments for the offering of atonement; the garments were not put on until after the sin offering was killed (v24).
v1-5: provide a summary of this whole chapter.
v12-13: Incense was offered on the altar; see Ex 30.34-38. Even the High Priest had to make an offering for himself "lest he die", see v 6,11,17. Even the best of men are only men at best.
Phil Moore (Straight to the heart of Revelation, p112) comments that the fire from the bronze altar was to be used to burn the incense. 'Jesus wants to make sure that we do not treat prayer as a work of the flesh, trying to win something from God through our own efforts and self-exertions.'
v16: There were offerings for all the uncleanness of the Israelites and all their sins. The people remained sinful, and the Most Holy Place itself was effectively contaminated, even after their sacrifices. The repetition of the sacrifices was indication of their inefficacy (Heb 10.1-4).
The verse says that the Tabernacle was "in the midst of their uncleanness." Here is a striking contrast, of pure and unclean so close together; yet here too is the provision for God's people to be clean.
v17: No man was to be present in the Tabernacle, except the High Priest; all of the sins of the nation wee his responsibility. Christ suffered alone, and entered the Most Holy Place alone for us (Heb 9.12); although He died in the midst of the people, what He did was hidden from them.
v18-19: Even the altar for sacrifices had to be purified from the uncleanness of the people.
v20-22: The scapegoat (also v10, and 14.53). This teaches separation from sins. The goat would bear away all the people's sins. This points clearly to Christ, who bore away our sins in His own body.
v26-28: Men appointed to take outside the camp the scapegoat, and to remove and burn the remainder of the offerings, were also unclean, and had to wash, and to remain outside the camp for the rest of the day.
v29-34: The Day of Atonement was an important day, at the end of the year. On this day, there was cleansing from all the people's sins.
It seems the offering of blood offering provided forgiveness. The scapegoat made the consciences of the people from free personal guilt, symbolically the goat took away their sins.
Tradition has it that, when the goat was finally released, this was communicated to the worshippers; ‘the goat has borne upon him all their iniquities into a land not inhabited’ (Alfred Edersheim, The Temple, its Ministry and Services)