In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Imaam Ibnul Qayyim [rahimahullaah] said:
The heart does get sick just as the body gets sick and its cure is found in repentance and bring keen [to obey Allaah and the Messenger etc]. The heart does become rusty just as a mirror becomes rusty, and remembrance of Allaah polishes it. The heart does become unadorned just as the body, and fear of Allaah beautifies it. The heart does suffer from discomfort just as the body suffers from discomfort due to hunger, and its food and drink are knowledge and awareness of Allaah, love of Allaah, reliance upon Allaah, turning sincerely to Allaah in repentance and obedience with Tawheed, and carrying out acts of obedience to Allaah. [An Excerpt from ‘Al-Fawaa’id 143’]