Greetings The Architect,
The reason I say religion is man's creation is because of the varying number of interpretations of His message that are out there.
If all religions were simply various interpretations of one message, then we should not expect them to be contradictory to each other: one says there is only one God, while others say this God has a son/daughter, others say there are many Gods and others say there is no God. Clearly, only one of these descriptions can be right, since God would not like His servants to be saying things about Him that are incorrect and offensive and attributing His power to others.
You believe that the prophet Muhammad had it right. I believe that Muhammad was a liar and that Jesus has it right and is, in a sense, God, based upon the concept of the Trinity.
I actually believe that both Muhammad and Jesus, peace be upon them, "had it right", and it makes sense that if the two were sent by God, then they should have the same essential message. Both of them taught that One God should be worshipped, though in the case of Jesus, people deviated from his teachings and created their own religion. By following the way of Muhammad (peace be upon him), I am following the main message brought by all the previous Prophets aswell.
But you see, all these prophets who were inspired by God to spread His Word, they all believed in their own beliefs to be the true Word.
All the Prophets were sent by God to convey
His message, not their own, or else we would be following a man-made law and not a divine one. They did of course believe themselves to be on the true path, and this was the same path for all of them: to worship one God only.
There are very slight differences in beliefs, like Islam's belief of the sin "shirk" for example. God's Word never changes. But Christianity is different. Jesus is God incarnate. He came down to not destroy the old laws, but to fulfill them, to make them easier to understand, to make His Word clearer.
In Islam, each of the Prophets had laws that were specific to their own peoples, and the law that is valid today is the law of the Prophet who was sent to us: all of mankind, Muhammad (peace be upon him). So while they all conveyed the same core message of monotheism, they had different laws to live by.
According to the Qur'an, Jesus' message is mentioned as follows:
3:50
"'(I have come to you), to attest the Law which was before me. And to make lawful to you part of what was (Before) forbidden to you; I have come to you with a Sign from your Lord. So fear Allah, and obey me.
3:51
"'It is Allah Who is my Lord and your Lord; then worship Him. This is a Way that is straight.'"
So he didn't come to make God's Word "clearer", as we believe that God is not incapable of conveying His message clearly, but to
confirm what had already come before him of God's Word, and make slight changes to other aspects of the previous law.
So basically, Christianity is correct. Jesus, being not only God but also a man, started a religion. It was the "man part" of Jesus, the "prophet part" (yes I'm making these terms up. so what? ;D) that made Christianity.
So you believe that Jesus made his own religion, which is why you say that religion is a "man's creation"? In Islam, it is unthinkable to associate God with His own creation: He has absolute control over everything, so to say that He became a part of what He created, while He is free from imperfection and His creation is not, is degrading His Majesty and Greatness and He is in fact far above such lowly descriptions. There is no need for God to appear on earth in the form of anyone, since He sends Prophets to convey His message.
Furthermore, much of the Bible cannot be considered to be Jesus' own words, let alone God's, so how do you know what his true teachings were?
Peace.
