10. Iman means to believe in and accept sincerely all those things to which the Messenger of Allah and this Book invite; and As-salihat are those righteous deeds which are performed in accordance with the guidance of Allah and His Messenger. The righteous deed of the heart and mind is that man’s thinking and his ideas and his intentions should be right and pure. The righteous deed of the tongue is that man should refrain from talking evil things, and whatever he says should be just and right and true. And the righteous deed of the limbs is that man'’s entire life should be spent in Allah’s worship and in obedience to His commands and law. Two results of the belief and righteous deeds have been mentioned: (1) That man’s evils will be wiped off; and (2) that he will be rewarded for the best of his deeds better than what he will actually deserve.
Wiping off of evils means several things: (1) All kinds of sins that man might have committed before his affirmation of the faith will be pardoned as soon as he believes; (2) the errors that man might have committed after the affirmation of the faith due to human weakness, but not because of a rebellious attitude, will be overlooked in view of his good deeds; (3) man’s self reform will automatically take place when he adopts a life of belief and righteousness, and most of his weaknesses will be removed from him.
The sentence, “We shall reward them for the best of what they used to do” has two meanings: (1) Man will be given his rewards on the basis of the best of his deeds; and (2) he will be rewarded better and more handsomely than what he will actually deserve for his deeds. This thing has been stated at other places also in the Quran. For instance, in (Surah Al-Anaam: Ayat 160), it has been said: “He who will bring a good deed before Allah, will receive a tenfold reward for it”, and in (Surah Al-Qasas: Ayat 4): “Whoever brings a good deed, shall have a better reward than that”, and in (Surah An-Nisa: Ayat 40): “Indeed Allah does not wrong anyone even by a jot: if one does a good deed, He increases it manifold.”