Imam Ali (peace be upon him): Abu Ma'mar al-Sa'dani narrates: A man came to the service of Imam Ali (peace be upon him) and said: "O Amir al-Mu'minin (peace be upon him), I have doubted the revealed Book of Allah, which says: 'Today We forget them just as they forgot the meeting of this day of theirs' (A'raf/51); and He has also said: 'They forgot Allah, so He [too] forgot them' (Tawbah/67); and He said: وَ ما کانَ رَبُّکَ نَسِیًّا [And your Lord is not forgetful]. So once He informs that He forgets, and another time He informs that He does not forget." ... Imam Ali (peace be upon him) said: "... As for His word: 'They forgot Allah, so He [too] forgot them' (Tawbah/67), it means nothing but that they forgot Allah in the abode of this world and did not act in obedience to Him, so Allah forgot them in the Hereafter — that is, He did not place anything for them in His reward, and they became forgotten. And likewise is the interpretation of the word of Allah the Mighty and Majestic: 'Today We forget them just as they forgot the meeting of this day of theirs' (A'raf/51). By forgetfulness He means that He will not reward them as He rewards His friends who were, in the abode of this world, obedient and remembering when they believed in Him and in His messengers and feared Him in secret. And as for His word: وَ ما کانَ رَبُّکَ نَسِیًّا — indeed our Lord, blessed and exalted, is not the one who forgets, and is not unaware; rather He is the Preserver, the All-Knowing, the All-Aware. The Arabs, in the matter of forgetfulness, say: 'We have forgotten so-and-so, and he does not mention us,' meaning that he did no good to them and did not mention them with good. So have you understood what Allah the Mighty and Majestic has mentioned?" He said: "Yes."