يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا لَا تُبْطِلُوا صَدَقَٰتِكُم بِٱلْمَنِّ وَٱلْأَذَىٰ كَٱلَّذِى يُنفِقُ مَالَهُ رِئَآءَ ٱلنَّاسِ وَلَا يُؤْمِنُ بِٱللَّهِ وَٱلْيَوْمِ ٱلْءَاخِرِ ۖ فَمَثَلُهُ كَمَثَلِ صَفْوَانٍ عَلَيْهِ تُرَابٌ فَأَصَابَهُ وَابِلٌ فَتَرَكَهُ صَلْدًا ۖ لَّا يَقْدِرُونَ عَلَىٰ شَىْءٍ مِّمَّا كَسَبُوا ۗ وَٱللَّهُ لَا يَهْدِى ٱلْقَوْمَ ٱلْكَٰفِرِينَ

Some soil (earth) may collect on the surface of a boulder. Outwardly, it appears as though this is good, fertile soil, but when a gust of wind brings a rain-shower down upon it, then the earth is washed away, leaving the rock exposed to the elements. The same is true of one who has donned a superficial robe of piety, without that piety having permeated his entire being. Should he be addressed rudely by someone asking for financial help, or should his ego receive a wounding blow, he becomes so irritated that he exceeds all bounds of decency in his response. Incidents of this nature are like the showers of rain which wash away his outward garb of piety, leaving his true nature exposed to the outside world. To do things for God’s sake, is to give priority to the invisible over the visible world. It is to set one’s sights on an unseen world, over and above the world which meets the eye. This requires a loftiness of vision. Those who show such sublimity of vision have the door of God’s realization opened to them.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (2:264)