Imam Ali (AS) said, Beware of letting your [lower] self overwhelm you in that which it presumes [of this world] while you do not overcome it in that which you are certain [of the Hereafter], for indeed this is from the gravest of evils.
الإمامُ عليٌّ (عَلَيهِ الّسَلامُ) : إيّاكَ أنْ تَغْلِبَكَ نَفْسُكَ على ما تَظُنُّ وَلاتَغْلِبَها على ما تَسْتَيْقِنُ فإنَّ ذلِكَ مِنْ أعْظَمِ الشَّرِّ