The sinner does not feel any remorse over his sins, that is because his heart is already dead
Ibn Qayyim Al-JawziyyaThe heart becomes sick, as the body becomes sick, and its remedy is al-Tawbah (repentance) and protection [from transgression]. It becomes rusty as a mirror becomes rusty, and its clarity is obtained by remembrance. It becomes naked as the body becomes naked, and its beautification is al-Taqwa. It becomes hungry and thirsty as the body becomes hungry, and its food and drink are knowledge, love, dependence, repentance and servitude.
Ibn Qayyim Al-JawziyyaWhen there is money in your hand and not in your heart, it will not harm you even if it is a lot; and when it is in your heart, it will harm you even if there is none in your hands.
Ibn Qayyim Al-JawziyyaThe ibtilaa' (testing) of the believer is like medicine for him. It cures him from illness. Had the illness remained it would destroy him or diminish his reward and level (in the hereafter). The tests and the trials extract these illnesses from him and prepare him for the perfect reward and the highest of degrees (in the life to come).
Ibn Qayyim Al-JawziyyaHow is it possible for oneโs heart to be certain that one is going to meet Allah, that Allah sees and hears all that he does, and knows his secret open affairs, and that he will be made to stand before Allah, answerable for all his deeds - how can one be certain and aware of all of this, and yet persist upon things which displease Allah; persist upon abandoning Allahโs orders, neglecting His rights, and yet claim that he has good expectation of Allah?
Ibn Qayyim Al-Jawziyya