Wallatheena amanoo waAAamiloo assalihati lanukaffiranna AAanhum sayyi-atihim walanajziyannahum ahsana allathee kanoo yaAAmaloon (surah Ankabut: 7)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(29:7) Those who believe and do good deeds, We shall cleanse them of their evil deeds and reward them according to the best of their deeds. *10

Wallazeena aamanoo wa `amilus saalihaati lanukaf firanna `anhum saiyiaatihim wa lanajziyannahum ahsanal lazee kaanoo ya`maloon

*10) Iman means to believe in and accept sincerely all those things to which the Messenger of Allah and this Book invite; and "good works" are those which are performed in accordance with the guidance of Allah and His Messenger. The good work of the heart and mind is that man's thinking and his ideas and his intentions should be right and pure. The good work 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 good work 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 their deeds", 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 Qur'an. For instance, in Surah Al-An`am. :160, it has been said: "He who will bring a good deed before Allah, will receive a tenfold reward for it", and in Surah AlQasas :4: "Whoever brings a good deed, shall have a better reward than that", and in Surah An-Nisa :40: "Indeed Allah dces not wrong anyone even by a jot: if one does a good deed, He increases it manifold. "