Faith increases, decreases and vanishes
Faith increases by obligatory and voluntary obedience and decreases by sins: Minor and major; and faith vanishes by disbelief and polytheism. Allah (may He be Exalted) says (which means): "The believers are only those who, when Allah is mentioned, feel a fear in their hearts and when His Verses (this Quran) are recited unto them, they (i.e. the Verses) increase their Faith." [Surat Al Anfal: 2]. Allah says (which means): "And that the believers may increase in Faith (as this Qur'ân is the truth)." [Surat Al Muddathir: 31]. Allah also says (which means): "He it is Who sent down As-Sakînah (calmness [...]