1. Christ, who accomplished the perfect atonement (The Day of Atonement) (Lev 23:27) Lev 17:11, Heb 9:12, Heb 7:27, Heb 10:9-12, 14

God commanded the Israelites to commemorate and keep the Day of Atonement. At this time, the high priest entered the Holy of Holies and offered a sacrifice for atonement for all the sins of himself and the people of Israel. (Lev 23:27)

Lev 23:27 Also on the tenth day of this seventh month there shall be a day of atonement: it shall be an holy convocation unto you; and ye shall afflict your souls, and offer an offering made by fire unto the Lord.

Since the life of the flesh is in the blood, an innocent person must shed blood for our sins to be forgiven. (Lev 17:11)

Lev 17:11 For the life of the flesh is in the blood: and I have given it to you upon the altar to make an atonement for your souls: for it is the blood that maketh an atonement for the soul.

In order to make us perfect, Jesus entered the sanctuary once for all, having obtained eternal redemption once for all with His own blood. (Hebrews 9:12, Heb 7:27, Heb 10:9-14)

Hebrews 9:12 Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us.

Heb 7:27 Who needeth not daily, as those high priests, to offer up sacrifice, first for his own sins, and then for the people’s: for this he did once, when he offered up himself.

Heb 10:9 Then said he, Lo, I come to do thy will, O God. He taketh away the first, that he may establish the second.
10 By the which will we are sanctified through the offering of the body of Jesus Christ once for all.
11 And every priest standeth daily ministering and offering oftentimes the same sacrifices, which can never take away sins:
12 But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God;
13 From henceforth expecting till his enemies be made his footstool.
14 For by one offering he hath perfected for ever them that are sanctified.