Day of Atonement

Concise Bible Dictionary:

This was one of the most solemn days in the whole year, being, in common with the Sabbath, the only occasion on which the people were commanded to cease from work entirely. On the day of atonement they were also to afflict their souls, and that by a statute forever (Lev. 16:29-3129And this shall be a statute for ever unto you: that in the seventh month, on the tenth day of the month, ye shall afflict your souls, and do no work at all, whether it be one of your own country, or a stranger that sojourneth among you: 30For on that day shall the priest make an atonement for you, to cleanse you, that ye may be clean from all your sins before the Lord. 31It shall be a sabbath of rest unto you, and ye shall afflict your souls, by a statute for ever. (Leviticus 16:29‑31)). The time of the year in which the day fell — the tenth day of the seventh month — is very significant, especially when viewed in connection with the other feasts. See FEASTS.
The rites prescribed for the Day of Atonement are given (Lev. 16; Lev. 23:26-3226And the Lord spake unto Moses, saying, 27Also 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. 28And ye shall do no work in that same day: for it is a day of atonement, to make an atonement for you before the Lord your God. 29For whatsoever soul it be that shall not be afflicted in that same day, he shall be cut off from among his people. 30And whatsoever soul it be that doeth any work in that same day, the same soul will I destroy from among his people. 31Ye shall do no manner of work: it shall be a statute for ever throughout your generations in all your dwellings. 32It shall be unto you a sabbath of rest, and ye shall afflict your souls: in the ninth day of the month at even, from even unto even, shall ye celebrate your sabbath. (Leviticus 23:26‑32); Num. 29:7-117And ye shall have on the tenth day of this seventh month an holy convocation; and ye shall afflict your souls: ye shall not do any work therein: 8But ye shall offer a burnt offering unto the Lord for a sweet savor; one young bullock, one ram, and seven lambs of the first year; they shall be unto you without blemish: 9And their meat offering shall be of flour mingled with oil, three tenth deals to a bullock, and two tenth deals to one ram, 10A several tenth deal for one lamb, throughout the seven lambs: 11One kid of the goats for a sin offering; beside the sin offering of atonement, and the continual burnt offering, and the meat offering of it, and their drink offerings. (Numbers 29:7‑11)). In the first we have a detailed account of the peculiar work appointed for the high priest on that day; in the second, we learn what had been shortly expressed in Leviticus 17, how the people should comport themselves on that day; and in the third we are told of certain sacrifices which were to be offered up besides those spoken of in Leviticus 16. In this passage we learn that the Day of Atonement was a gracious provision in order that the relationship of the people with the holy God who dwelt among them might be maintained.
The points to be noticed are
2. Aaron must offer sacrifices for himself and his house; a young bullock for a sin offering and a ram for a burnt offering. Aaron and his sons represent the saints who now form the church as a company of priests, and were thus, in the type, distinct from the people (Israel) as an earthly company who formed the camp.
3. For the congregation two goats were taken for a sin offering, and a ram for a burnt offering. On the two goats the lot was cast, and the one on whom the lot fell was for Jehovah, and was offered as a sin offering. This, as with the bullock for Aaron and his house, was the atonement offering Godward. The other, after being presented before the Lord, was brought forth: on him Aaron laid both his hands and confessed over him “all the iniquities of the children of Israel and all their transgressions in all their sins, putting them upon the head of the goat,” (Lev. 16:2121And Aaron shall lay both his hands upon the head of the live goat, and confess over him all the iniquities of the children of Israel, and all their transgressions in all their sins, putting them upon the head of the goat, and shall send him away by the hand of a fit man into the wilderness: (Leviticus 16:21)), which was then sent away into the wilderness, a land of forgetfulness. In the two goats we have the two sides of atonement, namely, that which meets the character and holiness of God, and that which meets the need of the sinner as to the removal of his sins. (See ATONEMENT.)
4. Atonement was made for the holy place, for the tabernacle, and for the altar, because of the uncleanness of the children of Israel.
The day of Atonement being once a year — once every year, by a perpetual statute — stands in strong contrast to the one perfect sacrifice of the Lord Jesus, by which the believer is perfected in perpetuity. (See Heb. 10:1-181For the law having a shadow of good things to come, and not the very image of the things, can never with those sacrifices which they offered year by year continually make the comers thereunto perfect. 2For then would they not have ceased to be offered? because that the worshippers once purged should have had no more conscience of sins. 3But in those sacrifices there is a remembrance again made of sins every year. 4For it is not possible that the blood of bulls and of goats should take away sins. 5Wherefore when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me: 6In burnt offerings and sacrifices for sin thou hast had no pleasure. 7Then said I, Lo, I come (in the volume of the book it is written of me,) to do thy will, O God. 8Above when he said, Sacrifice and offering and burnt offerings and offering for sin thou wouldest not, neither hadst pleasure therein; which are offered by the law; 9Then said he, Lo, I come to do thy will, O God. He taketh away the first, that he may establish the second. 10By the which will we are sanctified through the offering of the body of Jesus Christ once for all. 11And every priest standeth daily ministering and offering oftentimes the same sacrifices, which can never take away sins: 12But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God; 13From henceforth expecting till his enemies be made his footstool. 14For by one offering he hath perfected for ever them that are sanctified. 15Whereof the Holy Ghost also is a witness to us: for after that he had said before, 16This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them; 17And their sins and iniquities will I remember no more. 18Now where remission of these is, there is no more offering for sin. (Hebrews 10:1‑18)).

From Manners and Customs of the Bible:

The Great Day of Atonement took place on the tenth day of the seventh month, Tisri, corresponding to our October. It was a day of great solemnity, especially designated and kept as a fast day (see Lev. 23:2727Also 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. (Leviticus 23:27); Num. 29:77And ye shall have on the tenth day of this seventh month an holy convocation; and ye shall afflict your souls: ye shall not do any work therein: (Numbers 29:7); compare Psa. 35:1313But as for me, when they were sick, my clothing was sackcloth: I humbled my soul with fasting; and my prayer returned into mine own bosom. (Psalm 35:13); Isa. 58:55Is it such a fast that I have chosen? a day for a man to afflict his soul? is it to bow down his head as a bulrush, and to spread sackcloth and ashes under him? wilt thou call this a fast, and an acceptable day to the Lord? (Isaiah 58:5)) and in later times was known by the name of The Fast. Acts 27:99Now when much time was spent, and when sailing was now dangerous, because the fast was now already past, Paul admonished them, (Acts 27:9). On this day the high priest, clad in plain white linen garments, brought for himself a young bullock for a sin offering and a ram for a burnt offering; and for the people two young goats for a sin offering, and a ram for a burnt offering. The two goats were brought before the door of the Tabernacle, and by the casting of lots one was designated for sacrifice and the other for a scapegoat. The high priest then slaughtered the bullock and made a sin offering for himself and family. He next entered the Most Holy Place for the first time, bearing a censer with burning coals, with which he filled the place with incense. Taking the blood of the slain bullock, he entered the Most Holy Place the second time, and there sprinkled the blood before the mercy-seat. He next killed the goat which was for the people’s sin offering, and, entering the Most Holy Place the third time, sprinkled its blood as he had sprinkled that of the bullock. Some of the blood of the two animals was then put on the horns of the altar of incense, and sprinkled on the altar itself. After this the high priest, putting his hands on the head of the scapegoat, confessed the sins of the people, and then sent him off into the wilderness. He then washed himself, and changed his garments, arraying himself in the beautiful robes of his high office, and offered the two rains as burnt offerings for himself and for the people (Lev. 16).