وَمَنْ خَفَّتْ مَوَازِينُهُ فَأُولَٰئِكَ الَّذِينَ خَسِرُوا أَنفُسَهُم بِمَا كَانُوا بِآيَاتِنَا يَظْلِمُونَ (9)
(7:9) and those whose scales are light will be the losers, *9 for they, are the ones who have been unjust to Our signs.
*9). For a full appreciation of this point it is necessary, to remember that man's deeds will be classified into positive and negative categorics. The positive category will consist of knowing the truth, believing in it, acting upon it, and striving to make it prevail. It is such acts alone which will have weight in the Hereafter. Conversely, whenever someone follows and goes after lusts or blindly follows other humans or satans, his acts will be reckoned as 'negative'. Such acts will not only be of no value at all, but will also have the effect of reducing the total weight of one's positive acts.
Thus, a man's success in the Hereafter requires that his good acts outweigh his evil ones to such an extent that even if his evil acts cause the effacement of some of his good acts, he should still have enough left in his credit to ensure his scale is inclined towards the positive. As for the man whose evil acts outweigh his good acts, he will be like the bankrupt businessman who, even after spending all his assets, remains under the burden of debt.