Now that you have understood the rational and traditional merits and characteristics of the presence of heart, as well as the disadvantages of neglecting it, (you should know that) understanding alone is not enough, though it strengthens the evidence. So, use all your endeavors and try to acquire that which you have understood, and turn your understanding into practice in order to be benefited by it and get its advantage. Think a little, as, according to narratives from the infallible Ahlul Bayt (AS ) -who are the sources of revelation, and all their knowledge and utterances are of divine inspirations and Muhammadan (SA) intuition [kashf] -the acceptance of the salat (by Allah) is the condition for the acceptance of other acts of worship. If the salat is rejected, they will not pay attention to the other acts at all.  The acceptance of the salat is conditioned by the presence of heart. Without the presence of heart in the salat it would be worthless and not becoming of being in the Presence of Allah and cannot be accepted, as had been explained by formerly mentioned hadiths. Thus, the key to the treasury [ganjinah] of deeds and the entrance to the doors of all kinds of happiness is the presence of heart, with which the door of happiness is opened to man, and without it all worships are degraded and worthless.
Now, with a look of regard, contemplate a little, and with the eye of insight look at the importance and the greatness of the situation, and carry it out with complete seriousness. The key to the door of happiness and the doors of Paradise, as well as the key to the door of wretchedness and the doors of Hell are in this world, in your own pocket. You can open the doors of Paradise and happiness to yourself, and you can be on the contrary. The reigns are in your hands. Allah, the Exalted, has completed the evidence for you, showed you the roads to happiness and wretchedness, and has offered you the outward and the inward successes. What was needed on the part of Allah and His friends [awliya], has been done. Now it is our turn for action. They are the guides and we are the treaders. They did their work as best as possible without the least negligence, such that there remained no excuse whatsoever. So, you, too, wake up from your sleep of negligence and tread upon the road to happiness and make use of your years and powers, since, if you waste your cash of years and youth, and your treasure of power and ability, no compensation can make up for them. If you are young, do not let yourself reach old age, because old age has its particular shortcomings which are known to the elderly people, and you do not know. To reform oneself in old age and in weakness is quite difficult. If you are old, do not let the rest of your years waste away, because, at any rate, as long as you are alive, you still have a way to happiness, and a door of happiness is open to you -God forbid its being closed and the road being blocked, as in that case you lose your free will and there remains nothing but regret, remorse and repentance of the past, of which you have no portion.
So, my dear, if you believe in what has been said, which is the sayings of the prophets (AS ), and if you prepare yourself for attaining to happiness and for the journey to the Hereafter, and find it necessary to obtain the presence of heart, which is the key to the treasure of happiness, the way to obtain it is to remove, first, the obstacles which prevent the presence of heart and to uproot the thorns from the road of the journey, and then to practice it. The obstacles which prevent the presence of heart in worship are the dispersion of the mind and too many engagements of the heart. They happen most frequently from outside and through the outer senses, such as the ear hearing some sound during worship and the mind is, thus, distracted, stirring the imagination and inner thoughts, which fall under the effect of fancy, flying from one branch to another. Or a person's eye may see something which disturbs the mind and distracts the thoughts. Likewise, other senses may be attracted, causing imaginative transitions.
Regarding the doing away with these obstacles, they have said that it is done by removing the causes, such as standing in a dark place, or in a privacy, when performing the salat, and closing the eyes during the salat, and refraining from performing it in places causing mental distraction. The late prosperous martyr (the Second Martyr) (may Allah be pleased with him), quotes some devotees to have said that they used to worship and perform their salats in a small dark room barely large enough for worshipping.  Yet, it is obvious that this would not remove the obstacle, nor would it uproot the cause, because the principal hindrance is the imagination, which, with even a little motive, does its job. It may sometimes happen that in a very small, dark and private room, the activities of imagination and fancy become greater, and they cause more (mental) plays, and jests. So, uprooting the whole matter is done by reforming one's imagination and fancy. Later on we shall return to this point. However, this type of treatment is sometimes effective and helpful in some souls, but we are looking for a decisive cure and uprooting the real cause, and it cannot be done that way.
Sometimes the disturbance of mind and absence of heart are caused by inner matters, which, generally speaking, are originated by two big causes to which return most of the matters:
One is the dissoluteness and volatileness of the bird of imagination. Imagination is, indeed, an extremely slippery power. It flies from one branch to another and from a peak to a peak. This is not connected to loving the world or paying attention to worldly matters, wealth or position. Actually, the volatility of imagination is, in itself, a calamity that afflicts even the ascetics. Acquiring calmness of mind, peace of soul and repose of imagination are of the important affairs which, if acquired, can bring about the final remedy. This shall be referred to later on.
The other cause is the love of the world and the attraction of mind to mundane matters. This cause is at the top of the sins and it is the mother of the inner diseases, the thorn of the road of the people of suluk and the source of disasters, As long as the heart loves this world and is indulged in it, the way to reforming the heart is closed and the door of all happiness is shut in the face of man. We shall, within two chapters, refer to these two big origins and strong obstacles, if Allah wills.
. See footnote 17.
. at Tanbihatul 'Aliyah 'Ala Waza'ifis Salatil Qalbiyah, p. 110 (printed within a collection of the statements of the Second Martyr, lithographed in 1313 H., by the handwriting of Muhammad Hasan Jarfadaqani).