Brothers and Sisters! Rasoolullaah Sallallaahu Alayhi Wasallam, taught us that Allah Almighty does not look at our appearances, instead He looks at our hearts and our deeds. So the heart is the concern of Allah, and if the heart is unstained and pure, then the body will also be unstained and pure. On the other hand, if the heart is diseased and impure, then it will affect the whole body. The heart is also the place where you either love or fear Allah, and it is also the place of the niyat - your intention, which will improve your actions for Allah to accept. The Prophet Sallallaahu Alayhi Wasallam said, The reward of deeds is dependant on your intentions and every person will get the reward according to what he has intended.
Imam Ibn Qayyim, May Allah have mercy on him said, that the most noble part of the body is the heart.
It is that part which accepts Allah, by always seeking ways and means to get closer and to love Allah. It is the place where Faith originates and it is also the organ which can be reached and touched by means of sincere communication. The heart is the key by which the other parts of the body are utilized and guided, just like Allah makes use of his us.
The Messenger of Allah always used to swear by saying, In the Name of the One who changes the heart. Some of his supplications were, Oh Allah, the One Who changes hearts, stabilize our hearts to perform good actions and deeds.
Imam Ibn Qayyim, May Allah have mercy on him said, If you can imagine the situation of the heart with reference to Allah and the Shaytaan, you will discover and perceive many incredible issues. For example - if it is affected by Allah, the heart will relax, open and react with sincere feelings like, love for Allah, love and pity for your brother and renounce the pleasures and emotions regarding worldly issues. If we find ourselves in this situation then our life will be wholesome and complete. While on the other hand, the situation of the heart with reference to the Shaytaan - it, full of fear, worry and sadness, have doubt as will be closed, dark and dismal far as righteousness is concerned, have greed for this world, and show disregard for Allah.
My Beloved Brothers and Sisters! The heart gets hard like a rock or maybe even harder. When it becomes like this, it will result in Allah Almighty abandoning that person, because the most remote heart is the one which is hard. This heart is ignorant, it will not show any response to communication or wisdom, and the person affected will have a heart like a stone, always causing evil or disaster. There are some hearts that will have sincerity and humbleness towards its Creator, and will perform deeds and actions which will result in getting closer to the Mercy of Allah. This heart will always be looking forward to do good.