The question about the Qur'ân's teachings on the Fall of man and redemption of mankind could be answered with two very short statements: 1. Although the Qur'ân contains the story of man's temptation and moral failure in Paradise, there is no Fall of man. 2. Mankind does not need redemption from sin.
If we want to explain these statements, we have to investigate into three sources. 1. the Qur'ân: What does the Qur'ân teach? 2. Muslim theology: How were the Qur'ânic teachings interpreted by Qur'ân commentators? 3. Tradition and folkislam: What has been added to the teachings of the Qur'ân by Muslim tradition or folkislam (popular Islam)? Tradition after Muhammad's death increasingly gained importance, and nowadays authentic tradition claims the same authoritative positon as the Qur'ân itself (in Christianity, the enormous importance of tradition can be observed in the Roman Catholic Church). Additionally, folkislam often plays a more important role for the individual Muslim than the very teachings of the Qur'ân, not to speak of Qur'ân commentaries of Muslim theologians. Therefore, nobody will be able to describe the exact idea of redemption of virtually all Muslims (Muslim theologians and illiterates, al-Azhar students and peasants etc.) in Indonesia, Saudi-Arabia or even the USA alike. We can only hint at some statements in the Qur'ân, in Qur'ân commentaries and in tradition.
As mentioned above, the Qur'ân does not contain the dogma of original sin. If we keep in mind that Muhammad came into contact with Christians in his environment und took over into the Qur'ân much material from the Bible (especially stories of Old Testament prophets), it is no wonder that many teachings of the Qur'ân correspond with Old and New Testament teachings. On the other hand, Islamicists today believe that Christians of Muhammad's time in the 7th century A. D. lacked an Arabic translation of the Bible. Their belief seems to have been mostly founded on other sources like apocryphical writings and oral traditions. The Christians Muhammad came into contact with held much heretical teachings (for example: Mary is the third person of Trinity) and abstruse dogmas. The consequence is that the Qur'ân does not contain fundamental statements about Christianity like the dogma of original sin. One can therefore assume that Muhammad did not hear the dogma of original sin from those Christians, except the fact that the Qur'ân speaks about Adam's being in Paradise:
In contrast to the Old Testament (Gen 2,19: "... God brought them unto Adam to see what he would call them: And whatsoever Adam called every living creature, that was the name thereof".), Allâh does not ask Adam to give names to the animals which were created by Allâh. On the contrary, the Qur'ân teaches that Allâh taught Adam the names of the animals. Afterwards, Allâh asked the angels, which names had been given to the animals. They do not know and answer: "Praise be unto thee, we have no knowledge, but what you teach us, for you are knowing and wise" (2,32). Adam is then asked to tell the angels the names of the animals, and this bears evidence for the pre-eminence of Adam before them. Then Allâh commands the angels to bow down before Adam. All angels obey except Iblis (another word for Satan in the Qur'ân) who refuses because of his pride (2,34).
But now temptation approaches to Adam and his wife in the shape of Satan: Satan leads man "to transgress" and forfeit paradise (2,36). Sura 20,120 tells us that Satan tempted him to transgress. Allâh had already warned Adam that Satan may possibly expel Adam out of paradise (20,117-119). Nevertheless, Adam and his wife ate from the forbidden tree. They realized their nakedness and made themselves clothes out of leaves (2,121). Being unable to stay longer in paradise, Allâh turns them out of it (7,22) and banishes them down to earth. It is quite interesting to note, that in contradiction to the Old Testament, Adam and his wife asked Allâh for forgiveness. At the same time, they emphasize that their sin affects only themselves (7,23): "They said: "We have sinned against our own souls" (7,23). Not Allâh, but they themselves are the ones who are affected by the violation of Allâh's commandement. The Qur'ân teaches us in many other instances that man always commits sin against himself and that sin can not affect Allâh. In our paradise-story, Allâh forgives Adam and his wife their transgression (2,37). According to the Qur'ân, Adam's sin in paradise has no further effects on mankind and does not hamper or destroy man's relationship to Allâh.
This transgression is so to say only a "faux pas", a lapse which stands in contradiction to Old Testament teaching. In the Qur'ân, the trespass does not destroy a former close relationship between Allâh and mankind. Although the Qur'ân teaches that Adam and his wife could not remain in paradise because of their sin, the event does not seem to be significant or to have such traumatic results for the history of mankind as in the Old Testament. The quality of relationship between man and his wife is not influenced by the Qur'ânic paradise-story either. The only result for Adam and his wife seems to be their banishment down to earth and the prophecy of enmity between man and Satan in the coming future (2,36). In spite of this transgression, Adam was "chosen" by Allâh, and "he accepted him and turned unto him again und directed him" (20,122).
Thus the Qur'ânic view is much more optimistic than the biblical one, concerning man's ability to live righteously. Mankind after Adam is not generally 'caught' in sin and need not be redeemed in order to perform good works. Man is able to live a godly life, if he resiststhe attacks of Satan. Consequently, the most wicked sin is, according to the Qur'ân, not to doubt Allâh's trustworthiness and reliability (as Gen 3,1 puts it: "Yea, has God really said ...?"), but man's will to determine his own destiny. It is his pride which makes him unable to submit to Allâh.
2. Relationships between people are not affected, since Adam's sin could not poison interhuman relationships.
3. After his banishment out of paradise, man is still able to live righteously, if he resists the whispering of Satan. Temptation approaches from the outside to him, not from his inner heart. Sin is not rebellion against God, but only "transgression" or a "trespass" (2,36). With this view, life on earth is like a time of probation and test which Allâh poses upon man. Consequently, the Qur'ân does not know of man's inner conflict between his will to perform the good and his inability to do it, as Paul describes it in Rom 7. Not the inner heart of man is evil, as the Bible tells us, but man's temptation comes from the outside, from Satan, the fallen angel, who was expelled from heaven and now tries to seduce man to perform evil. Man has the free choice between good and evil, although many people do not chose the right side. But this is only Allâh's testing. The Old and New Testament also expect man to do good works, but at the same time, both make unmistakably clear that it is impossible for man to do these good works without the power of God. Moreover, all the good deeds one could perform would never suffice to save a single soul. A single transgression of God's law can never be eradicated through good deeds, but still is reality, until the sinner asks Jesus Christ for forgiveness.
4. Interestingly enough, according to Muslim theology, there are persons who are sinless: All prophets mentioned in the Qur'ân have never committed any sin, according to Muslim theology, but not according to the Qur'ân! Thus, also the prophet Jesus committed no sin, but nevertheless was only a human being. The Qur'ân itself reports several times that many of the prophets asked Allâh for forgiveness for their sins (Adam in 7,23; Noah in 11,47; Abraham in 14,41; Moses in 28,16; David in 38,24; Muhammad in 110,3; 48,2). The islamicist Louis Gardet considers the 10th century to be the time when the dogma of sinlessness was first reported. It seems to have originated with the Shî'î branch of Islam. In the 8th century, Shî'î Muslims had already defended this dogma in regard to their leaders, the Imâms.
The Qur'ân does not teach in a single verse that Muhammad was sinless. On the contrary, Muhammad confesses several times to have been a mere human being. In early Islam, evident errors and faults of Muhammad were not at all taboo, even if they were often minimized. Muslim theology had been especially emphasized that Muhammad kept himself away from the idolatry of his compatriots. Muslim theologians are at variance as to whether Muhammad never committed any error or fault only at the time when he received his revelation and performed his different tasks as the leader of his people or whether this sinlessness also extends to matters of everyday life. Another question of dispute is whether Muhammad and the other prophets were sinless all their lifes or only from the time of their calling as Allâh's prophets; whether they were free from minor and major sins or whether prophets could perhaps perform smaller sins due to carelessness or forgetfulness.
5. Without original sin, no redemption is necessary. E. E. Elder summarizes: "Islam has no doctrine of sin, but only of sins, the great problem being the classification of disobedient acts into the categories of great and small and determining their respective punishments ... To Christian thinkers sin is a state of rebellion against the righteousness and holiness of God".
If it comes to the question of salvation, it is necessary that every human being submits himself to Allâh and accepts Islam, since there will be no mercy on non-Muslims at the Day of Judgement. According to tradition, only Muhammad can intercede for Muslim believers as intercessor (!); the Qur'ân itself gives only some hints at the possibility on intercession. From Muslim tradition we know the following prayer to Muhammad:
"You are the beloved,
to whose intercession we look forward
at the Great Day of Judgement,
to which all people will flock.
You are the intercessor,
to whose intercession we look forward
on the narrow path,
when your foot slips.
Then be my intercessor,
when I lay in my grave
and am your guest,
since a guest is to be honoured".
Thus conversion to Islam is no redemption, but obedience towards Allâh.
6. The idea of juridical representation is unknown to Islam. Each one is responsible only for himself and acts only for his or her own person. The Old and New Testament teach us that Adam has sinned as representative for all human beings (Rom 5,12) and with this destroyed the relationship of every single human being to God. In the same manner, Christ by sacrificing himself, has obtained redemption for His church, so that nobody else has to die for his sins.
7. In the eyes of Muslim theologians, this idea of representative redemption is unlogical and absurd. Muslim theologians have argued that this representative redemption had no effects, since otherwise redemption would have set an end to all sorts of sin, of theft, murder or adultery. But it is evident that mankind has not changed since Jesus' death and continues to committ sins. Muslim theology does not realize that also the saved one has his freedom to perform evil, that Satan rules the world until the Last Day and that Jesus' redemption does not work magically in all people, whether they want it or not.
8. Since Islam holds Jesus not to be the Son of God, redemption can never be accepted by Muslim theology. The Old and New Testament teach clearly that only God himself could be the redeemer of mankind. An animal, being offered as sacrifice could not take away sins (Hebr 10,4: "For it is not possible that the blood of bulls and of goats should take away sins"; see also Hebr 9,12-14). Also no other human being could save any other soul: 1. The death of Isaac would not have helped mankind. It would have been only an act of obedience by Abraham 2. Even when Moses asked God to be eradicated from the Book of Life so that Israel could be saved in his place, God did not allow this to happen (Ex 32,32; see a similar wish of Paul in Rom 9,3). Psalm 49, 7-8 summarizes: "None of them can by any means redeem his brother, nor give to God a ransom for him: For the redemption of their soul is precious". One condition for Jesus' ability to redeem His people, was his holiness and sinlessness as the Son of God. This sonship of Jesus is clearly rejected by the Qur'ân.
 In this article, I will use 'Allâh' only for the Qur'ânic god, whereas I use 'God' exclusivly for the Biblical god.
 This is summarized by Hermann Stieglecker out of different Qur'ân commentaries: Die Glaubenslehren des Islam, Paderborn 1962/1983, p. 191.
 ibid., p. 190
 Thus defined by Tilman Nagel, Der Koran, Einführung-Texte-Erläuterungen, München 1983, p. 239.
 Louis Gardet, Islam, Köln 1968, p. 68
 Stieglecker, op. cit. p. 472-473
 W. Madelung reports some standpoints of Muslim theology in his article 'Isma, in: Encyclopaedia of Islam, Vol. iv, Leiden, 1990, p. 182-184
 E. E. Elder, The Development of the Muslim Doctrine of Sins and their Forgiveness, in: The Moslem World 29/1939, S. 178-188, here p. 188
 Retranslated from Constance E. Padwick, Muslim Devotions, A Study of Prayer-Manuals in Common Use, London 1960, p. 44
 Stieglecker, op. cit. p. 317