Without the Son of God and His desire to do what needed to be done on our behave, man would earn his own salvation and pay for his own sins.
This is what Islam teaches, that man earns his own salvation.
Christ, God's Son, died for our sins (on the cross) according to the inspired Word of God (1 Cor. 15:3,4)
For Christians...Sin is proud, independent rebellion against God in active or passive form (Rom 1:18-23 3:10,23)
For Islam...Sin is failure to do Allah's will, failure to do one's religious duties as outlined in the 5 Pillars of the Faith. In other words...it's all on their shoulders for not living up to what God expected of them....just like it does in Judaism.
In Matthew 11:28,30 the bible says "Come to me, all you who are weary and burdened, and I will give you rest...For my yoke is easy and my burden is light"
As Christians we have assurance of salvation if we abide in Christ.
Choose you this day which you will serve....a dead prophet (a man) that left the 5 pillars in people's laps to deal with and no assurance of salvation....... or Christ the Living Savior (God), who will free anyone who truly believes.