Had Shaytaan repented, even his work would have been accomplished. Hazrat Maulana Ashraf Ali Thanwi (Rahmatullah Alaihe) explains that Shaytaan had within him three, ?’s (Arabic alphabet) but was lacking in one (?):           

1.      He was an ????. One who worships Allah Ta'ala. Such a worshipper of Allah was he, that not even a span of earth exists whereupon his head has not prostrated.

2.      He was an ????. One who recognizes. He recognized Allah Ta'ala  to such an extent that on the very occasion Allah when Allah Ta'ala anger was directed at him and he was told,

“Begone! Verily you are rejected one.”

 He still implored Allah Ta'ala because he was fully aware of the fact that Allah Ta'ala is absolutely free of prejudice and reaction based on emotion and will not be swayed and overcome by His anger. Even in that state he was confident of his Dua being accepted. He had such recognition of Allah Ta'ala.

He was   ????.  One who has knowledge. He was an Aalim of such a caliber that he knew all the finer details of the Shariah of all the Messengers.

What was lacking was one (?)

3.      He was not an ????. He was not an intense lover of Allah Ta'ala. Had he possessed the (?) of Ishq, the intense love of Allah, he would not have been accursed and rejected. Had he been an Ashiq, he would not have opposed Allah Ta'ala but would have rather become restless at the displeasure he has caused to the Truly Beloved and fallen headlong into prostration and said that which Hazrat Adam (Alaihis Salaam) said:

???????? ????????? ???????????

“O our Nourisher and Sustainer, we have wronged our souls.”

(Extracted from “the virtues of Taubah”)