“...without shedding of blood there is no forgiveness.” Hebrews 9:22

Most people and even many who profess to be Christian do not associate Christmas with the atoning work of Jesus Christ. Many would prefer to visualize Jesus in a manger rather than on a cross. But the bible is perfectly clear - Jesus was born to die even the death on a cross (Phil.2:8). 

We know that Jesus died at Calvary and was our sacrifice for sin but I want to highlight another Bible word that describes His role, His purpose for living and dying.
On the cross he ‘atoned’ ...He became our “atonement.” 

A good way to impress this truth on our hearts is to think of “atonement” as in two words. The first being “at” and the second being “onement.” Or, “at one.” In other words, our ‘oneness’ in Christ has been accomplished through His death. The death of Jesus Christ has made us ‘one’ with God. Those for whom Christ died, they are ‘at one’ with Him because Christ turned God’s wrath away from all those He chose, in Christ from eternity out of pure grace.

Jesus being our “atonement” allows us to see that God being holy and just must either inflict punishment for sin or either assume it upon Himself. Praise the Lord He chose the latter. Jesus who is God, satisfied God’s holy wrath by bearing our sin and the punishment our sin deserved - so he died in our place. He atoned for us. 

I love what William Farley says on this: 
The cross confirms...... the infinite offense of sin. It says that no finite sacrifice can atone for sin (Heb. 10:4). Nothing but a sacrifice of infinite value, God Himself, can atone for our offenses. In addition, no one but an infinite Being is capable of suffering sufficiently to atone for infinite offenses against an infinitely holy God. [Grace quotes]