Allah mentions this story in Surat Al-Baqarah, at the beginning of Surat Al-A`raf, in Surat Al-Hijr, Al-Isra', Al-Kahf and here. Before creating Adam, peace be upon him, Allah told the angels that He was going to create a human being from sounding clay of altered smooth black mud. He told them that when He finished creating and forming him, they were to prostrate to him as a sign of honor and respect, and out of obedience to the command of Allah, may He be exalted. All of the angels obeyed this command except for Iblis, who was not one of them. He was one of the Jinn, and his nature betrayed him at his time of greatest need. He refused to prostrate to Adam, and he disputed with his Lord about him, claiming that he was better than Adam, because he was created from fire while Adam was created from clay, and fire was better than clay, or so he said. He made a mistake by doing this, and he went against the command of Allah, thus committing the sin of disbelief. So Allah exiled him, humiliated him, and cast him out of His mercy and His sacred Presence, and called him "Iblis" symbolizing that he had Ablasa min Ar-Rahmah (despaired of mercy) -- that there was no hope for him of mercy. He cast him down from the heavens, disgraced and rejected, to the earth. Iblis asked Allah to give him a reprieve until the Day of Resurrection, so the Forbearing One, Who does not hasten to punish those who disobey Him, gave him a reprieve. When he knew that he was safe from destruction until the Day of Resurrection, he rebelled and transgressed.

فَبِعِزَّتِكَ لأغْوِيَنَّهُمْ أَجْمَعِينَإِلاَّ عِبَادَكَ مِنْهُمُ الْمُخْلَصِينَ

(Iblis said: "By Your might, then I will surely mislead them all, except Your true servants amongst them.") This is like the Ayat:

أَرَءَيْتَكَ هَـذَا الَّذِى كَرَّمْتَ عَلَىَّ لَئِنْ أَخَّرْتَنِ إِلَى يَوْمِ الْقِيَـمَةِ لأَحْتَنِكَنَّ ذُرِّيَّتَهُ إَلاَّ قَلِيلاً

(Iblis said: "See this one whom You have honored above me, if You give me respite until the Day of Resurrection, I will surely seize and mislead his offspring all but a few!") (17:62). These few are the ones who are excepted in another Ayah, which is:

إِنَّ عِبَادِى لَيْسَ لَكَ عَلَيْهِمْ سُلْطَـنٌ وَكَفَى بِرَبِّكَ وَكِيلاً

(Verily, My servants -- you have no authority over them. And All-Sufficient is your Lord as a Guardian.) (17:65)

قَالَ فَالْحَقُّ وَالْحَقَّ أَقُولُ

لاّمْلاّنَّ جَهَنَّمَ مِنكَ وَمِمَّن تَبِعَكَ مِنْهُمْ أَجْمَعِينَ

((Allah) said: "The truth is -- and the truth I say that I will fill Hell with you and those of them (mankind) that follow you, together.") Some of them, including Mujahid, read this as meaning, "I am the Truth and the truth I say." According to another report narrated from Mujahid, it means, "The truth is from Me and I speak the truth." Others, such as As-Suddi, interpreted it as being an oath sworn by Allah. This Ayah is like the Ayat:

وَلَـكِنْ حَقَّ الْقَوْلُ مِنْى لاّمْلأَنَّ جَهَنَّمَ مِنَ الْجِنَّةِ وَالنَّاسِ أَجْمَعِينَ

(but the Word from Me took effect, that I will fill Hell with Jinn and mankind together.) (32:13), and

قَالَ اذْهَبْ فَمَن تَبِعَكَ مِنْهُمْ فَإِنَّ جَهَنَّمَ جَزَآؤُكُمْ جَزَاءً مَّوفُورًا

((Allah) said: "Go, and whosoever of them follows you, surely, Hell will be the recompense of you (all) - an ample recompense.) (17:63).