The 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-JawziyyaFrom the perfection of Allah's ihsan is that He allows His slave to taste the bitterness of the break before the sweetness of the mend. So He does not break his believing slave, except to mend him. And He does not withhold from him, except to give him. And He does not test him (with hardship), except to cure him.
Ibn Qayyim Al-JawziyyaThe sinner does not feel any remorse over his sins, that is because his heart is already dead
Ibn Qayyim Al-JawziyyaLove of Allah is the power of the heart, the sustenance of the heart, the light of the heart.
Ibn Qayyim Al-JawziyyaHad Allah lifted the veil for his slave and shown him how He handles his affairs for him, and how Allah is more keen for the benefit of the slave than his own self, his heart would have melted out of the love for Allah and would have been torn to pieces out of thankfulness to Allah. Therefore if the pains of this world tire you, do not grieve. For it may be that Allah wishes to hear your voice by way of Dua'a. So pour out your desires in prostration and forget about it and know; that verily Allah does not forget it.
Ibn Qayyim Al-Jawziyya