As Allah made many graces available for man, he laid a great responsibility which the heavens, earth, and mountains could not bear. When man accepted this responsibility that he should worship only Allah, without any partner, Allah to test man made the Satan (devil) as an enemy for man. These Satan's provoke and tempt man to commit crimes and sins, because he doesn't realise his weak points which are being targeted.
The human is a creature who cannot relieve himself or cause it any harm, unless Allah wills. He cannot have any effect on his own life or death. The human being is a weak creature who cannot stand cold and heat, the sun or air. His body is not covered with wool or feathers. If a thorn pricks him, he may suffer from pain all night. Even a germ may cause his weakness or perhaps death.
Allah the exalted gives an example of the weakness of a human in the Holy Quran:
“And if any fly snatches away a thing from them, they will have no power to release it from the fly. So weak are (both) the seeker and the sought.” (22:73)
We can see from this great example that a human cannot even put up with a fly, or on the other hand the human still thinks he's a tough cookie because he may be a boxing champion, or a champion wrestler and according to his own beliefs, he will challenge anything coming in his ways, but for now forget challenging another human. What if a wasp was to come and sting him, he would be running around crying for help!
Remember, this is only the physical side of the human from which he suffers, but the main weakness is based in the internal, which in fact is the heart!
The heart is the foundation of the human body and if that remains weak so will the rest of the human structure.
All of the diseases of the heart are founded up on desires and doubts. The life of the heart and its illumination is the cause of all good to be found in it and its death and darkness is the cause of all evil to be found in it. There are many reasons why the heart is affected and these are due to the negative qualities of mankind, such as ignorance, impatience, pride, greed, disbelief and oppression. These negative qualities are the cause of the human heart becoming weak and ill, and in order to purify the heart, we need to find a cure.
Allah the Almighty has given us a cure for our heart, which is the Holy Quran.
The Quran is a cure for that which is in the heart and for the one who has the sickness of worldly desires, for it leaves certain knowledge and understanding from which the heart sees such a thing in accordance to their reality. It's not just about reading the Quran but understanding the Quran is where we slip up, and we miss out on the message which is given out to us and all the wisdom it contains. So once we fail to read and understand the Quran we obviously miss out on the most important issue which is acting upon the message, and the guidance of the Holy Quran which is the key to returning the heart into its normal state in which it was created, just as the body returns into its normal state upon being treated..
Remember once again, the heart forms the foundation, it is the owner of the limbs, the limbs are its soldiers, so when the owner becomes purified, its soldiers become purified, and when the owner becomes disgraced then its soldiers become disgraced.