This all presupposes the truth of Christian mythology, of course.
Well that hardly needs stating..
Why do we need saving? Saving from what?
We are under a death sentence for our sin.. We need saving from that death sentence so we may have eternal life in Gods perfect existence.
Atonement? Grace? -- myths; extrapolated animal sacrifice.
The animal sacrifices where but a sign showing the future sacrifice of the Messiah Jesus that would once and for all provide atonement for all whom would believe Jesus..
Sin? What's sin? Who decided what acts were sinful?
God... No comment
Hey you have answered that one for yourself. I need make no more comment