According to Islam's Hadith, if we do not sin, Allah will wipe us from the face of the Earth. Allah wants us to sin.
Sahih Muslim 6621— "Abu Ayyub Ansari reported that Allah's Messenger said: If you were not to commit sins, Allah would have swept you out of existence and would have replaced you by another people who have committed sin, and then asked forgiveness from Allah, and He would have granted them pardon."
Sahih Muslim 6622— "Abu Huraira reported Allah's Messenger having said: By Him in Whose Hand is my life, if you were not to commit sin, Allah would sweep you out of existence and He would replace (you by) those people who would commit sin and seek forgiveness from Allah, and He would have pardoned them."
According to Islam, who is mankind's saviour?
Qur'an 2:35-36— "We said: "O Adam! dwell thou and thy wife in the Garden; and eat of the bountiful things therein as (where and when) ye will; but approach not this tree, or ye run into harm and transgression." Then did Satan make them slip from the (garden), and get them out of the state (of felicity) in which they had been."
Qur'an 7:19-22— "O Adam! dwell thou and thy wife in the Garden, and enjoy (its good things) as ye wish: but approach not this tree, or ye run into harm and transgression." Then began Satan to whisper suggestions to them, in order to reveal to them their shame that was hidden from them (before). He said: "Your Lord only forbade you this tree, lest ye should become angels or such beings as live for ever." And he swore to them both, that he was their sincere adviser. So by deceit he brought about their fall."
Why do we sin today? We sin because Satan tempts us. In the Qur'an, after being judged, Satan vowed to lead us astray:
Qur'an 15:39— "Satan said: "O my Lord! Because you misled me, I shall indeed adorn the path of error for them (mankind) on the earth, and I shall mislead them all."
According to Islam, Allah's greatest adversary is Jesus, because Jesus absolutely refused to sin.
Sahih al-Bukhari 3286— "The Prophet said, "When any human being is born, Satan touches him at both sides of the body with his two fingers, except Jesus, the son of Mary, whom Satan tried to touch but failed, for he touched the placenta-cover instead."
Adam sinned. Noah sinned. Abraham sinned. Moses sinned. Muhammed sinned like it was going out of style, as if in competition to see who could sin the most and the worst. All of the prophets sinned, except for Jesus. Allah can forgive all of them, except Jesus. Jesus would not obey Allah's command to disobey. Allah tells us what the penalty is for not sinning. Complete annihilation. So according to Islam, Muhammad, the Qur'an, and the Hadith, Satan is the saviour of all mankind.