The Commander of the Faithfuls (a.s) said: “Take lesson from Allah’s action with respect to Iblis, for He annulled all his acts of worship (because of his arrogance); he had worshipped Allah for six thousand years, and you know not if they were of the years of the world or those of the hereafter (every day of which is equivalent to fifty thousand years of this world). And this was a consequence of a moment’s disobedience (in that he considered himself to be superior to Adam and refused to prostrate before him). So, after the Satan, is there anyone who can remain safe from Allah’s punishment by being disobedient to Him?”7
Imam Sadiq (a.s) was asked: “For what reason did Allah respite Iblis till the ‘appointed time’?”
The Imam (a.s) replied: “Because of his praise and thanksgiving to Allah.”
He (a.s) was asked again: “What was his praise and thanksgiving?”
He (a.s) replied: “His six thousand years of worship in the heavens.” (On another occasion he (a.s) said: “He offered, in the seven heavens, a two-rak’at prayer which extended for a period of six thousand years).”( Iblis Nameh, pg. 165; ‘Ilal al-Sharai’, vol. 2, pg. 243 )