The term "High Holidays" refers to Rosh Hashanah (the Jewish New Year) and Yom Kippur together. Literally "the Day of Atonement," Yom Kippur concludes the Ten Days of Awe. It is the holiest and most somber day of the year. (Lev. 23:27-32)
In ancient times, one day of the year, the High Priest entered the Holy of Holies to put the blood of the sacrificed animal on the altar as a sin offering. Through faith, obedience to God's precise instructions resulted in atonement, or covering, for sin. Today, Yom Kippur is a day of fasting and reflecting upon one's sin.
Yom Kippur can be somewhat of a conundrum to Jewish believers in Y'shua. Do we fast and confess our sins like the rest of the Jewish community or do we rejoice in the knowledge that we're forgiven in Messiah? Many Jewish believers view Yom Kippur as a time for identification with our Jewish people, introspection for ourselves and intercession for loved ones, knowing all the while that Jesus is the One that makes us at one with God.