The Prophet [SAW] said: "There are three things, whoever attains them will find therein the sweetness of Islam: When Allah [SWT] and His Messenger [SAW] are dearer to him than all else; when he loves a person and only loves him for the sake of Allah [SWT]; and when he would hate to go back to disbelief as much as he would hate to be thrown into the fire."  

عَنِ النَّبِيِّ ﷺ قَالَ ثَلاَثٌ مَنْ كُنَّ فِيهِ وَجَدَ بِهِنَّ حَلاَوَةَ الإِسْلاَمِ مَنْ كَانَ اللَّهُ وَرَسُولُهُ أَحَبَّ إِلَيْهِ مِمَّا سِوَاهُمَا وَمَنْ أَحَبَّ الْمَرْءَ لاَ يُحِبُّهُ إِلاَّ لِلَّهِ وَمَنْ يَكْرَهُ أَنْ يَرْجِعَ إِلَى الْكُفْرِ كَمَا يَكْرَهُ أَنْ يُلْقَى فِي النَّارِ