How can we reconcile the secret sin that eradicates good deeds with the fact that Allah does not waste the reward of those who do good?

The hadith referred to has been a subject of scholarly disagreement regarding its authenticity and interpretation. The noble verse: {Indeed, We do not allow to be lost the reward of any who did well in deeds} does not mean that a good deed, once completed, will never be lost. Rather, it refers to one who performs good deeds intending thereby the Face of Allah and following His law. As for one whose deeds are not good, such as those who commit polytheism, hypocrisy, or disdain (for religion), their deeds may be annulled, as stated in the hadith of Thawban concerning people who come with deeds like mountains, but Allah renders them as scattered dust.