وَاعْلَمُوا أنَّهُ مَا مِنْ طَاعَةِ اللهِ شَيْءٌ إلاَّ يَأْتي فِي كُرْه، وَمَا مِنْ مَعْصِيَةِ اللهِ شَيءٌ إلاَّ يَأْتِي فِي شَهْوَة. فَرَحِمَ اللهُ رَجُلاً نَزَعَ عَنْ شَهْوَتِهِ، وَقَمَعَ هَوَى نَفْسِهِ، فَإنَّ هذِهِ النَّفْسَ أَبْعَدُ شَيْء مَنْزِعاً، وَإنَّهَا لاَ تَزَالُ تَنْزِعُ إِلَى مَعْصِيَة فِي هَوىً.
You should know that every obedience to Allāh is unpleasant in appearance while every disobedience to Allāh has the appearance of enjoyment. Allāh may have mercy on the person who kept aloof from his desire and uprooted the appetite of his heart, because this heart has far-reaching aims and it goes on pursuing disobedience through desires.