(CNN) -- Here's a look at the Jewish holiday Yom Kippur, the Day of Atonement.
September 22-September 23, 2015 - Yom Kippur will begin at sundown on September 22nd and end at nightfall on September 23rd.
The Day of Atonement is considered the most important and sacred of Jewish religious holidays. It falls on the tenth day of the Jewish lunar month of Tishri.
Other Facts: The dates in the Jewish calendar known as the "10 days of repentance" begin with Rosh Hashanah (New Years Day) and end with Yom Kippur.
On Yom Kippur, devout Jews atone for their sins from the past year. They ask for forgiveness from God and from other people.
It is a day of fasting, repentance and worship. On this day no work is permitted, one is not allowed to bathe, wear leather footwear or have marital relations.
Yom Kippur is found in the Bible in Leviticus 16:1-34; 18:1-30 and in Numbers 29: 7-11.
The services during Yom Kippur are held continuously through the day and include readings from the Torah and the reciting of penitential prayers.
Yom Kippur services conclude with closing prayers and the blowing of the shofar-a ritual musical instrument carved from the horn of a ram.