Start with wrong assumptions, and invariably you will end up with wrong conclusions. The problem is that it is quite difficult to recognize what the assumptions of any system actually are. Humans take so much for granted, whether due to our culture, our religion, or our experiences, that we get locked into one way of thinking without seeing why our own invalid assumptions are leading us to incorrect conclusions.
Consider God’s mechanism for forgiveness. Just how do humans receive forgiveness? Do you just ask for it or is there something else required? In both Christianity and Islam, to gain forgiveness requires repentance. On the surface, someone might conclude both religions are similar. Yet as usual, when a person digs deeper, a great theological divide emerges.
To unravel this difference, let’s go all the way back to the beginning, Adam’s disobedience. In Christianity, the fall of man is an incredibly significant event. Adam’s sin initiated a sequences of events, one of which was causing sin to afflict the entire human race (Romans 5:12). The ground was cursed, and Adam was informed that he would once again return to dust (Genesis 3:19). Death had now entered the world, and God’s creation, created in His own image, would now perish. In Islam the story is similar, but with a critical difference. Adam’s sin is viewed by Islam as having no lasting consequence. According to the Qur’an (2:37), Adam asked for forgiveness and received it. As far is Islam is concerned, that’s the end of the story. For example, one Muslim web site puts it this way,
Therefore, even though the Quran mentions the sin of Adam and how he was banished from the Garden, it places no responsibility on the shoulders of his progeny. [i]
So here is the critical difference. In Christianity, the fall of man was the beginning of the sin nature of man, a curse which always ends in death. How does a just God simply ignore our sinful nature? Even if a person repents of a sin, there are myriad more to deal with. What about the underlying problem of the heart now governed by the propensity to sin (Jeremiah 17:9)? Conversely, in Islam, the mistake of Adam was followed by his repentance, and that was that. While Muslims are instructed to follow his example of asking for forgiveness, there is no original sin and therefore no other relevance.
How does this all tie back to the Christian and Muslim view of how to receive forgiveness? In Christianity, since humans are now inherently bent toward sin, there needs to be a mechanism not just to forgive any one particular sin, but rather to change our entire sin nature. Islam teaches that people are not inclined to sin, therefore repentance is all that is required. In the 4th century, Athanasius commented on this errant view,
“Had it been a case of a trespass only, and not of a subsequent corruption, repentance would have been well-enough; but when once transgression had begun men came under the power of the corruption proper to their nature…” [ii]
In other words, Athanasius recognized that if you start with the assumption that man was not corrupted by the fall, you will come to the conclusion that repentance alone would be sufficient to regain a right standing with God. However, with the realization that the entrance of sin into the world had permanent ramifications, the mechanism for repentance would require help from God Himself.
“His part it was, and His alone, both to bring again the corruptible to incorruption, and to maintain for the Father His consistency of character with all.” [iii]
So how does man, who now has a sinful nature, return to his state before the fall? Here God foresaw the dilemma and therefore had already made provision for the solution. He Himself would come, and conquer death (Romans 5:19). By so doing, He maintained consistency with His command that sin would result in death, but also with His goodness in that His creation, once corrupted, would have a way of reconciliation and thus would not fade into nonexistence from death and permanent separation from Him.
The point in all this is that Islam starts with a flawed assumption, that sin did not pass into all humanity from the fall of Adam. If you start with that assumption, you will invariably come to the wrong conclusion that repentance, apart from Christ, would be enough (Qur’an 110:3). In this one aspect, I must admit Islam is internally consistent. However, since man does have a sinful nature, there must be a way for that repentance to have efficacy. That way is provided by God Himself via the death of His Son (Romans 5:18).
Without an understanding of the intrinsic sinful nature of man, it is logical to not understand the need for a Savior.