The day of atonement is one of the most significant day in the nation of Israel. It's spiritual significance is so unique because it is the one day of the year where the entire nation standstill because of the high priest will be able to enter into the holy of holies. On this day, the high priest starts by offering a sacrifice first for his own sin. Then 2 goats are picked and with one chosen as a sacrifice for the people's sin. The other is chosen to be a scapegoat. This scapegoat is made to carry all of the sins of the people of Israel as it is led into the wilderness.
You will notice that Christ by his death on the cross of calvary, fulfills all 3 roles; he is high priest though he does not need to offer an sacrifice first for his sins. He is also the first goat whose blood is shed for the people. Lastly, he is the scapegoat led into the wilderness. It is the reason Christ was not crucified within the city, he died at Golgotha, outside the city.
