Causes hardening of the heart.. The heart attached to worldly things and rely on them and forget about the Hereafter

To hardening of the heart for many reasons, numerous and some are more dangerous than the other, the more severe the more varied reasons, and perhaps most important of these reasons include the following: 
1 - the heart becoming attached to worldly things and rely on them and forget the Hereafter:
This is one of the greatest reasons that harden the hearts, the love of the world if dominated by the love of the hereafter attached to the heart, and weak faith little by little until the worship heavy boring, and find joy and his behavior in this world and debris to forget the Hereafter, or nearly so, and lose sight of the Killjoy, and start him along hope, and met these scourges in person only Ohlkth.What the people of this world and the heart to the capital and one of them
However, after the obsessed, and then to later so away from God U, and then fall at the position of God, do not care about God in any of the valleys of the lower valley perished, God forbid. 
This person forgot the Lord and turned to the minimum Cila her honor, Vazm what does not deserve veneration, and underestimated what deserves veneration and reverence and honor, so the consequences are of the worst consequences. Says a predecessor: ((no Abdul only has eyes in the face he sees them is lower, and the eyes in his heart, he sees them to the Hereafter, and if God wanted Abdul good open the eyes, which in his heart, Vibsr them what God promised the unseen, and if he wanted it so on the left, and then read {or are their hearts locked up} (Muhammad: 24). 
2 - absent-mindedness: the disease and Bill, and a serious illness if you got the heart, and enables the soul, and took on Aljorah and chilling led to lock all the doors of guidance, and for printing and seal on their hearts {those who print of God on their hearts and their hearing and their eyes and those are the heedless} ( Bees: 108). 
Ibn al-Qayyim ', describing the event more of creation: ((It is hoped the event this character and found them all but a few of those who overlooked their hearts for the remembrance of Allaah, and they follow their own lusts, and become their own affairs and interests Virta, any Frtoa with benefit them and return Besalham, and worked to no avail them but because Bdhararham and sooner than later)) quote. 
He told the God of the owners of negligence they are the hearts of the harsh lived and relentless, would not be used with some advice, they are like stone or more severe, and they have eyes watching the phenomena of things, but they do not see the facts, and they are distinguished between the benefits and disadvantages, and they have ears they hear the wrong such as lying, singing, obscenity, backbiting and gossip do not benefit them to hear the truth from the Book of Allah and the Sunnah of Prophet Muhammad 'How then to those to win and survive and that their situation, and that I have the guidance and integrity and that their way of Almighty says: {And We have Dhirona for Hell many of the jinn and humans, have hearts wherewith they understand not and they have eyes wherewith they see not and ears do not listen to them by those who are astray like cattle, but those are the heedless} (customs: 179).
3 - associated with bad friends, and sit in the skies corrupt: This is why it is the most common reasons influence, because the human vulnerable to those around him, a person who lives in the center filled with sins and evils, and sits more people they talk about the pleasures forbidden and women, and increased their jokes and laughter and jokes and listening to music and see the series, this person must be affected by these companions and print stolen from Tabahm, Fikso his heart and make mistakes, and get used to these evils.
4 - many fall into sin and evil into something so familiar: 
The sin even if they are small, they pave the way for her sister until the sequence of sin and trivialize her, do not realize the owner danger, and leaks and one behind the other to his heart, so do not care about her, not able to separate from her and asks what is more, weak in his heart to maximize the God and to maximize its limits. It also weakens the functioning of the heart to God and the house the other and hinder or stop do not let him take one to God by step, Guilt obscure connecting, and cut stepper, Linux and the student, so says the Prophet '((if a person commits a sin jokes in his heart a black spot, if he repents and disarmament and ask forgiveness refine his heart, and increases until Talo his heart, that Arran, who said God Ran {Nay, but on their hearts what they earn? (Mutaffifin: 14).
5 - to forget death and Skrath, and the horrors of the grave and the torment and blessing, and the development of scales, and the dissemination of bureaucracy, and traffic on the path, and forget about the fire, and Allah has prepared the hearts of cruel owners.
6 - busy with things that spoil the heart and Iksé: The heart is five things that invalidate the values ​​I mentioned a large number of the mixture, and riding the Sea of wishful thinking, and without attachment to God, and overeating, and excessive sleeping.