This is the day that Yahweh established, once a year, to make general and overall atonement (amends) for all the sins of the people; sins that had not been brought before him with a sacrifice to receive atonement. It was a time set aside to repair the damaged relationship between Yahweh and the people of  Israel.  Even sins of ignorance, sins that people did not realize they had made, were included in this atonement.  Therefore on the Day of Atonement, Israel is reconciled to Yahweh, which is necessary before the Festival of Tabernacles, the festival which foreshadows the in-gathering of  His people.

Yahweh’s instructions indicate that only what is clean and pure is acceptable to him, both people and things.
The Scriptures use the word "Saint" for an individual who is truly Yahweh’s. The definition of a Saint, from both Hebrew and Greek, is "pure one."  So one must be a "pure one" to be acceptable to Yahweh.  How can one be a "pure one"?  Keep the commandments of Yahweh and faith in Yahshua for your atonement (Rev. 14:12), and live your life by Messiah’s example of both behavior and attitude.
 Everything had to be cleansed and made pure before being presented before Yahweh. On the Day of Atonement this was to be made so for the ritual items and all the people of the nation at the same moment in time.  All the people of Yahweh will be pure at the same time and then will be the in-gathering.

The high priest was the only priest who could go into the Most Set Apart Place behind the curtain with the arc of the covenant, and then only once a year for this offering.

Levi 16:32 (KJS) And the priest, whom he shall anoint, and whom he shall consecrate to minister in the priest's office in his father's stead, shall make the atonement, and shall put on the linen clothes, [even] the {set apart} garments:
33 And he shall make an atonement for the {set apart} sanctuary, and he shall make an atonement for the tabernacle of the congregation, and for the altar, and he shall make an atonement for the priests, and for all the people of the congregation.
34 And this shall be an everlasting statute unto you, to make an atonement for the children of Israel for all their sins once a year. And he did as {Yahweh} commanded Moses.
The atonement (repair, make right) for the building, the alter, the other priests and all the people was to make everything clean before Yahweh.  It is evident from the following verses that the atonement (making amends) for sin by animal sacrifices freed the person from guilt, as a criminal is released after serving his time in jail, but the records still existed, Yahweh still kept the "rap sheet," so to speak.  The Day of Atonement was a day of the people saying they were sorry, again, for the sins on that "rap sheet."
Hebr 10:1 (NIV) The law is only a shadow of the good things that are coming--not the realities themselves. For this reason it can never, by the same sacrifices repeated endlessly year after year, make perfect those who draw near to worship.
*The law, which defines sin, cannot make a person be good.  Something has to change a person’s attitude.
2 If it (the Law) could (make people perfect), would they (the sacrifices) not have stopped being offered? For the worshipers would have been cleansed once for all, and would no longer have felt guilty for their sins.
 *Perfect people need no atonement, and therefore no sacrifices.
3 But those sacrifices are an annual reminder of sins,
4 because it is impossible for the blood of bulls and goats to take away sins (sinning).
5 Therefore, when Messiah came into the world, he said:
"Sacrifice and offering you did not desire,
 *It is not sacrifice Yahweh wants, but a "pure one" whose attitude and behavior are not sin.
but a body you prepared for me;
6 with burnt offerings and sin offerings
you were not pleased.
7 Then I said, `Here I am--it is written about me in the scroll--
I have come to do your will, O {Yahweh}.'"

Messiah Yahshua serves as a permanent high priest.

Hebr 9:11 (NIV) When {Messiah} came as high priest of the good things that are already here, he went through the greater and more perfect tabernacle that is not man-made, that is to say, not a part of this creation.
12 He did not enter by means of the blood of goats and calves; but he entered the Most {Set Apart} Place once for all by his own blood, having obtained eternal redemption.
13 The blood of goats and bulls and the ashes of a heifer sprinkled on those who are ceremonially unclean sanctify them so that they are outwardly clean (their bodies).
14 How much more, then, will the blood of {Messiah}, who through the eternal Spirit offered himself unblemished to {Yahweh}, cleanse our consciences (our attitudes)  from acts that lead to death, so that we may serve the living {Mighty One}!

So, why does the Messiah’s sacrifice bring a better atonement than the animal sacrifices?

Hebr 9:15 (NIV) For this reason {Messiah} is the mediator of a new covenant, that those who are called may receive the promised eternal inheritance--now that he has died as a ransom to set them free from the sins committed under the first covenant (the covenant of atonement by animal blood).
Hebr 10:11 (NIV) Day after day every priest stands and performs his religious duties; again and again he offers the same sacrifices, which can never take away sins (they were forgiven, but not erased).
12 But when this priest had offered for all time one sacrifice for sins, he sat down at the right hand of {Yahweh}.
13 Since that time he waits for his enemies to be made his footstool,
14 because by one sacrifice he has made perfect forever those who are being {set apart}. *No need for a separate sacrifice for each individual and for each sin committed.
Psal 103:8 (KJS) {Yahweh} [is] merciful and gracious, slow to anger, and plenteous in mercy.
9 He will not always chide: neither will he keep [his anger] for ever.
10 He hath not dealt with us after our sins; nor rewarded us according to our iniquities.
11 For as the heaven is high above the earth, [so] great is his mercy toward them that fear him.
12 As far as the east is from the west, [so] far hath he removed our transgressions from us.
Hebr 10:16 (KJS) This [is] the covenant that I will make with them after those days, saith {Yahweh}, I will put my laws into their hearts, and in their minds will I write them;
17 And their sins and iniquities will I remember no more.
These verses in Hebrews and Psalms mean that the record, the "rap sheet," will be destroyed for those who "are being set apart."  No record will be kept; for the sins atoned for by the covenant in Messiah’s blood, it will be as if they had never happened.


Hebr 10:19 (NIV) Therefore, brothers, since we have confidence to enter the Most {Set Apart} Place by the blood of {Yahshua},
20 by a new and living way opened for us through the curtain, that is, his body,
21 and since we have a great priest over the house of {Yahweh},
22 let us draw near to {Yahweh} with a sincere heart (righteous motivation and attitude in our mind) in full assurance of faith, having our hearts sprinkled to cleanse us from a guilty conscience and having our bodies washed with pure water.
23 Let us hold unswervingly to the hope we profess, for he who promised is faithful.
24 And let us consider how we may spur one another on (to keep a right attitude)
toward love and good deeds.
25 Let us not give up meeting together, as some are in the habit of doing, but let us encourage one another--and all the more as you see the Day approaching.
26 If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left, *One cannot abuse Messiah’s sacrifice for us and keep on sinning; in this case, there is no more atonement.
27 but only a fearful expectation of judgment and of raging fire that will consume the enemies of {Yahweh}.

Hebr 10:35 (NIV) So do not throw away your confidence; it will be richly rewarded.
36 You need to persevere (continue in a righteous attitude and behavior) so that when you have done the will of {Yahweh}, you will receive what he has promised.
37 For in just a very little while,
"He who is coming will come and will not delay.
38 But my righteous one will live by faith.
And if he shrinks back,
I will not be pleased with him."
39 But we are not of those who shrink back and are destroyed, but of those who believe and are [will be] saved.


We were commanded in Leviticus to do this day forever: 

Levi 23:27 (KJS) Also on the tenth [day] of this seventh month [there shall be] a day of atonement: it shall be an [set apart assembly] unto you; and ye shall afflict your souls, and offer an offering made by fire unto Yahweh.
28 And ye shall do no work in that same day: for it [is] a day of atonement, to make an atonement for you before Yahweh your Elohim.
29 For whatsoever soul [it be] that shall not be afflicted in that same day, he shall be cut off from among his people. 30 And whatsoever soul [it be] that doeth any work in that same day, the same soul will I destroy from among his people.
31 Ye shall do no manner of work: [it shall be] a statute for ever throughout your generations in all your dwellings. 32 It [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.
But now we do this day as a memorial and to suffer in a token way, with thanks remembering how Messiah Yahshua suffered for us and looking forward to the last Day of Atonement just before the eternal kingdom begins.

References to "afflict your souls":
We know from study that "ye shall afflict your souls" means humble, abase, deal hard with oneself and to submit.  Scripture shows indirectly that the people did this by fasting.
Jona 3:5 (NIV) The Ninevites believed {Yahweh}. They declared a fast, and all of them, from the greatest to the least, put on sackcloth.
6 When the news reached the king of Nineveh, he rose from his throne, took off his royal robes, covered himself with sackcloth and sat down in the dust.
7 Then he issued a proclamation in Nineveh:
"By the decree of the king and his nobles:
Do not let any man or beast, herd or flock, taste anything; do not let them eat or drink.
8 But let man and beast be covered with sackcloth. Let everyone call urgently on {Yahweh}. Let them give up their evil ways and their violence.
9 Who knows? {Yahweh} may yet relent and with compassion turn from his fierce anger so that we will not perish."
10 When {Yahweh} saw what they did and how they turned from their evil ways, he had compassion and did not bring upon them the destruction he had threatened.

More specific to The Day of Atonement is Isaiah 58.  Here Yahweh is upset with the people’s attitude.  It seems that they think they can just fast on this day, leave the rest of their lives unchanged and be acceptable to Yahweh.

Isai 58:2 (NIV) For day after day they seek me out;
they seem eager to know my ways,
as if they were a nation that does what is right
and has not forsaken the commands of its {Elohim}.
They ask me for just decisions
and seem eager for {Elohim} to come near them.
3 `Why have we fasted,' they say,
`and you have not seen it?
Why have we humbled ourselves,
and you have not noticed?'
"Yet on the day of your fasting, you do as you please
and exploit all your workers.
4 Your fasting ends in quarreling and strife,
and in striking each other with wicked fists.
You cannot fast as you do today
and expect your voice to be heard on high.
5 Is this the kind of fast I have chosen,
only a day for a man to humble himself?
Is it only for bowing one's head like a reed
and for lying on sackcloth and ashes?
Is that what you call a fast,
a day acceptable to {Yahweh}?
6 "Is not this the kind of fasting I have chosen:
to loose the chains of injustice
and untie the cords of the yoke,
to set the oppressed free
and break every yoke?
7 Is it not to share your food with the hungry
and to provide the poor wanderer with shelter--
when you see the naked, to clothe him,
and not to turn away from your own flesh and blood?
8 Then your light will break forth like the dawn,
and your healing will quickly appear;
then your righteousness will go before you,
and the glory of {Yahweh} will be your rear guard.
9 Then you will call, and {Yahweh} will answer;
you will cry for help, and he will say: Here am I.

13 "If you keep your feet from breaking the Sabbath
and from doing as you please on my [set apart] day,
if you call the Sabbath a delight
and {Yahweh’s} {set apart}day honorable,
and if you honor it by not going your own way
and not doing as you please or speaking idle words,
14 then you will find your joy in {Yahweh},
and I will cause you to ride on the heights of the land
and to feast on the inheritance of your father Jacob."
The mouth of {Yahweh} has spoken.