The Muslims view of Allah is that of an elderly, cherubic Arab who is always happy when people obey him and furiously angry when they disobey – and he rewards or punishes them according to his happiness or anger. Even so, Muslims believe Allah can be merciful if he chooses. He accepts repentance and forgives faults and shortcomings.
The Koran teaches that forgiveness has to be sought because Allah is all-knowing. Allah sees the secrets of the heart – nothing escapes his notice. The Koran proclaims repeatedly that Allah forgives sins, but it is important to remember this distinction: forgiveness is purely the prerogative of Allah. There is no means by which a human being can know with certainty that he has been forgiven – other than a possible inference that since nothing bad has happened to him, he must have been forgiven.
Allah provides no means for man to be cleansed of sin because Islam does not recognize that man needs such cleanings. Judaism and Christianity disagree sharply – man has a sin nature from birth and sin must be cleansed. For the Jews, Jehovah provided a means of atonement through the blood sacrifices of the Mosaic Law. For the Christian, the ultimate atoning sacrifice was Jesus’ death on the Cross.