In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Allaah [The Most High] said: [أَوَلَا يَرَوۡنَ أَنَّهُمۡ يُفۡتَنُونَ فِى ڪُلِّ عَامٍ۬ مَّرَّةً أَوۡ مَرَّتَيۡنِ ثُمَّ لَا يَتُوبُونَ وَلَا هُمۡ يَذَّڪَّرُونَ – See they not that they are tried once or twice every year? Yet, they turn not in repentance, nor do they learn a lesson (from it)]. [9:126] – Meaning: By way of calamities, diseases and the divine laws; but they neither turn in repentance nor [abandon] the evil they are upon, nor do they learn a lesson regarding what will benefit, so that they may act upon it; nor regarding what is harmful to them, so that they may abandon it. Allaah [The Most High] put them to the test-and this is Allaah’s way with all the nations-through poverty [or loss in wealth]; loss of health, calamities and through commands and prohibitions, so that they might turn to Allaah, but they neither repent nor learn a lesson. In this Ayah is proof that Imaan increases and decreases and that it is obligated on the believer to examine his Imaan- pay close attention to it, improve and increase it [i.e. by way of the Qur’aan and authentic Sunnah], so that it constantly rises. [An Excerpt from ‘Tayseer Al-kareem Ar-Rahmaan Fee Tafseer kalaam Al-Mannaan by Imaam Sadi (rahimahullaah). Slightly paraphrased]