The most holy day of the year in the Jewish calendar begins at sunset tomorrow. Yom Kippur means “Day of Atonement” and its strict observance is commanded in Leviticus 16.
Arutz-7 has a summary of the significance of the day. It begins:
The highest of the High Holidays – Yom Kippur – is only about a day away, and Jews around the world are preparing by attempting to become better people.
Such a notion immediately distinguishes Judaism from Christianity. The latter denies the value of the law in helping one to become a better person (e.g., Rom 7:7-12). Instead, Jesus and his followers taught that one could become righteous only by trusting in one who was perfectly righteous. Indeed, Abraham was considered righteous without ever celebrating Yom Kippur (Gen 15:6).
Arutz-7 continues:
Yom Kippur, the Day of Atonement, is a Divinely-designated day that the Torah explains “will atone for you [plural] to purify you from all your sins before G-d.” Such atonement, however, must generally be accompanied by teshuvah, a process that includes introspection, confession of sins, remorse, and a commitment not to repeat them. One must also appease and ask forgiveness from those he has harmed or insulted over the year.
There is great value in repentance, and Jews and Christians would probably agree that it should not be limited to one time per year. But repentance is not sufficient for atonement. For that one needs the shedding of blood. As Leviticus 17:11 says,
For the life of the flesh is in the blood, and I have given it for you on the altar to make atonement for your souls, for it is the blood that makes atonement by the life.
The Arutz-7 article continues:
The prayers for Yom Kippur, which take up most of the day, are replete with the various concepts of teshuvah, as well as acknowledgement of G-d’s goodness in affording mortals this opportunity to exonerate and improve themselves.
Does this make God good? Is he good to give them the opportunity to make themselves better? God of course is always good. But if everyone who ever tried to make himself better failed, then ultimately God’s goodness accomplishes nothing. I can think of something better: how about if God atoned for my sin, removed my guilt, and declared me righteous? That would be much better.
Isaiah agreed and he predicted that a person would come who would do just that:
Isaiah 53:5 (ESV) But he was wounded for our transgressions; he was crushed for our iniquities; upon him was the chastisement that brought us peace, and with his stripes we are healed.
If those who are without atonement have reason to observe this day, how much more do those whose sin has been fully and finally forgiven.