Effectively, Christians believe God transferred the sin of mankind upon (a person of) Himself and had Himself killed at the hands of a bunch of Jews and Romans in order to forgive sin. On the other hand Muslims believe God simply forgives sin out of His Mercy without a need to kill Himself.
The Muslim view does in fact make more sense once an individual considers the Attributes of God and the history of sin.
The History of Sin
Does sin have a point of inception? It does. The concept of sin only came into existence due to God. Think about it; an individual down the road who happens to have sexual intercourse is commiting sin because he is doing this act in an unmarried state whilst the individual next door is doing the SAME act but not committing a sin as his actions are under the umbrella of marriage. Who set the criteria of what constitutes sin and what does not? God.
So Who brought the concept of sin into existence? God.
Did God kill Himself in order to bring the idea of sin into existence? No.
Think about it, if God can introduce the idea of sin without a need to kill Himself then surely you can believe God can forgive people without sacrificing Himself.
NOTE: For intellectual honesty purposes it must be stated there is a distinction between the idea of sin and the act of sin.
Attributes of God
The relevant attributes of God for the purposes of this article are:
*God being the Ever Living
*God being the Forgiver
We realise God does not die and is the Forgiver of sin; therefore the Christian belief of God dying for the sin of people is problematic but the Islamic belief of God forgiving without dying is in line with a consistent and correct view of God
So, do we need God to sacrifice Himself in order to forgive sinners? No. The Islamic view of God simply forgiving out of His Mercy is sufficient.
All this philosophising does throw further refutation upon the neo-Christian idea of atonement
More about Jesus and Christianity plus Islam:
Encouragement to learn about Islam:http://thefactsaboutislam.blogspot.com/2010/08/assyrians-and-arab-christians-please.html
The Brothers of Jesus: Who are they?http://yahyasnow.wordpress.com/2009/12/25/jesus-teaches-muslims-are-right/
Which incarnation? I personally feel both beliefs are gateways to paganism:http://thegrandverbalizer19.blogspot.com/2010/08/two-incarnations-god-became-dove.html