What do christians believe about atonement or making up sins?

Answer 1

Christians generally believe in what the bible says about atonement.

There are 69 references to the atonement of our sins by the blood of bulls and of goats in the Old Testament, but in the new Testament, in Hebrews, the Bible says:

10.4. For [it is] not possible that the blood of bulls and of goats should take away sins.

and the writer of Hebrews goes on to talk of Christ's sacrifice for our sins:

10.12. But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God;

And finally, here is the only reference to 'atonement' in the New Testament, which Christians do believe:

Romans 5.11. And not only [so], but we also joy in God through our Lord Jesus Christ, by whom we have now received the atonement.