This past week I've had some discussion with a very pleasant Muslim, here are 2 of his questions and my responses:

Question 1:

"How come God had to become a man and home come Jesus had to die on the cross for the sins of mankind?"

God has given us a law (either natural law written on our hearts that every person has, or the revealed law given in sacred writings). The penalty for breaking God's law is death.  Even if one is broken, you are a lawbreaker and guilty of punishment.

How is anyone forgiven and not condemned to an eternal death sentence?  In the law given to the prophet Moses, God established a blood sacrifice for sin.  This sacrifice showed people that the penalty for breaking God's law was death.  However, an animal was a substitutionary sacrifice, it was the substitute, it died to pay the penalty of the person who actually sinned.

All this was a foreshadowing of what God would accomplish in Jesus.  Jesus came not just as a prophet, speaking the words of God, but as a sacrifice, he himself said that he was come to 'save my people from their sins.'  Many times he made predictions of his own death and how he had come to do the will of the Father.  He came to be the sacrifice for the sins of his people.

Why would the Jesus have to die?  The animal sacrifices were done repeatedly, but one perfect sacrifice would pay the penalty of sin for all time.  God himself was our substitute and paid the penalty so we could be forgiven.  Jesus being sinless was the perfect sacrifice, perfectly innocent, not dying for his own sins but for others.  No human is perfect which is why God himself was the sacrifice.  For us to be in the presence of God, we need to be perfect and without sin.  Only the perfect sacrifice of Jesus which forgives sin is the only way to be good enough to be in God's presence.

What if Jesus didn't die?  We still need to be perfect to be in God's presence.  Even if we do good in this life and do our very best to follow God's law and turn from any wrong, everyone will fail.  Everyone will have broken some of God's law, so everyone is a lawbreaker, and God punishes lawbreakers -- He has to or else He wouldn't be a fair God.  No matter how much good we do, it is not God's nature to overlook sin.  God is perfectly holy, perfectly righteous, He cannot look on sin, and He certainly cannot dismiss it.  The price must be paid or else God is not a fair or just God.  If He overlooks sin, He has changed His rules; but His law says the penalty for sin is death and eternal separation from God.  Jesus being God and man is the mediator between man and God; he has restored a relationship between man and God by paying the price for sin.  Jesus is the only way to a right relationship with God, the only way sins can be forgiven.

Question 2:

"Is it logically possible that Jesus could have been a prophet and messenger of God? Why or Why not?"

He was a prophet but that was not his primary role.  He came to die according to the predetermined plan of God.  So much of his message focuses on his mission to do the will of the Father and secure the salvation of his people, saving them from their sin.  He didn't come merely to 'say' the will of God, but to 'do' the will of God.