Shaitan (شیطان) is the equivalent of Satan in Islam. While Shaitan (شیطان, from the root šṭn شطن) is an adjective (meaning "astray" or "distant", sometimes translated as "devil") that is applied only to Jinn, Iblis (Arabic pronunciation: [ˈibliːs]) is the personal name of the Devil who is mentioned in the Qur'anic account of Genesis. According to the Qur'an, Iblis (the Arabic name used) disobeyed an order from Allah to bow to Adam and as a result was forced out of heaven and given respite until the day of judgment from further punishment.
When Allah commanded all of the angels to bow down before Adam (the first Human), Iblis, full of hubris and jealousy, refused to obey God's command (he could do so because he had free will), seeing Adam as being inferior in creation due to his being created from clay as compared to him (created of fire).
It is We Who created you and gave you shape; then We bade the angels prostrate to Adam, and they prostrate; not so Iblis (Lucifer); He refused to be of those who prostrate."
- (Allah) said: "What prevented thee from prostrating when I commanded thee?" He said: "I am better than he: Thou didst create me from fire, and him from clay.
- Qur'an 7:11-12
It was after this that the title of "Shaitan" was given, which can be roughly translated as "Enemy," "Rebel," "Evil" or "Devil". Shaitan then claims that if the punishment for his act of disobedience is to be delayed until the Day of Judgment, that he will divert many of Adam's own descendants from the straight path during his period of respite. God accepts the claims of Iblis and guarantees recompense to Iblis and his followers in the form of Hellfire. In order to test mankind and jinn alike, Allah allowed Iblis to roam the earth to attempt to convert others away from his path. He was sent to earth along with Adam and Eve, after eventually luring them into eating the fruit from the forbidden tree.