Know that man's rational soul is a reality which, at the same time of its unity and perfect simplicity, has diverse aspects (growths = nasha'at), the principal ones of which are, generally, three:
The first aspect (growth = nash'ah) is the external mundane visible aspect, displayed in the apparent senses, and its lowest surface is the body.
The second is the aspect [nash'ah] of the barzakh world (the Isthmus, or the intermediate, world) displayed in the internal senses, the barzakhian (intermediate) body and "the mould of the ideal" [qalib-i mithali]".
The third is the invisible internal aspect [nash'ah], displayed in the heart and in its affairs.
The relation of each of these aspects to the other is that of the external to the internal, and of the manifestation to the manifested. This is the reason for the effects, the characteristics and the reactions of each of these aspects to permeate into the other aspects. For example, if the sense of seeing discerns something, it will have an effect on the barzakhian sense of seeing according to its aspect [nash'ah]. Then the effect is transmitted to the internal seeing sense of the heart according to its aspect [nash'ah]. In the same way the effects of the cordial aspect appear in the other two aspects. This, besides being proved by a strong and firm evidence, coincides with the conscience, too. Consequently, all the formal disciplines of the Shar' have their effect, or effects on the interior; and each of the good characters -which belong to the barzakhian status of the soul also has its effects on the exterior and interior. All the divine knowledge [ma'arif] and the true beliefs also have their effects on the two barzakhian and external aspects. For example, this belief that to have control over the kingdom of existence as well as the invisible and visible worlds belongs to Allah, and no other being has any control over them, except that permitted shadowy control, brings about so many spiritual perfections and good human moralities, such as depending on Allah and trusting Him, and pinning no hope on any creature. This is the mother of perfections and the cause of so many good deeds and commendable acts, and prevents one from committing evil practices. Likewise other sorts of knowledge, which are so numerous that these pages, as well as the broken pen of the writer, have no patience to count them nor to relate the effects of each one of them, since it needs writing a huge book which can be expected only from the powerful pen of the people of knowledge, or from a warm soul of "the people of ecstasy" [ahl-i hal]: My hand is short, while the dates are (high) on the date-palms". 
Similar is, for example, contentment [rida'] as a character, which is one of the human moral perfections. It is effective in purifying and polishing the soul, rendering the heart a place for special divine manifestations, elevating faith to a perfect faith, the perfect faith to tranquillity [tuma'ninah], tranquillity to its perfection, its perfection to vision [mushahadah], the vision to a perfect vision, its perfection to "reciprocal love" [mushahadah] (with the Beloved), the reciprocal love to its perfection, its perfection to courting [murawadah], the courting to its perfection, its perfection to union [murawadah], the union to its perfection, and to what neither I nor you can imagine. The character of contentment has a surprising effect on the kingdom of the body and on the formal marks and acts, which are leaves and branches. It changes hearing, seeing and other powers and organs into divine ones, and the secret of "I will be his hearing and seeing"  is somewhat manifested. As those stages have an effect, or rather, effects, on the appearance, they are also affected so surprisingly by the outer shape, all the ordinary and extraordinary movements and pauses, and all the acts and abstentions, so that it sometimes happens that a scornful glance by a salik at a servant of Allah causes the salik to fall from his high status to the lowest of the low, and this will need him years to make up for it.
Now, as our helpless hearts are weak and shaky, like the weeping willows, losing their stillness, by every gentle breeze, it would be, therefore, necessary, even in ordinary situations -one of which is the instance of choosing one's clothes -to observe the conditions of the heart and to take care of it. As the soul and Satan have quite firm snares and clever delusions which we are unable to understand, we have to do our best, as much as we can and is in our capacity, to resist them, and to ask, in all cases, Allah's help and support for success.
So, we say that as it has become clear that the exterior and the interior have reciprocal effects, the seeker for the truth and spiritual elevation has to avoid choosing such clothes and models which have bad effects on the spirit, deviate the heart from perseverance and remembering Allah, and turn the soul's direction to worldly matters. Do not think that Satan's delusions and the tricks of the evil-commanding soul are confined only to expensive and nice clothes and luxurious articles. Actually even by old and worthless clothes they may disgrace a man. Therefore, one should avoid seeking fame through clothes, or rather he should avoid all conducts contrary to the normal and the customary. He is to abstain from wearing highly luxurious clothes made of expensive materials and attractively and notoriously tailored, because our hearts are very weak and inconstant, and they slip by slightest distinction and deviate from moderation. It may often happen that a wretched, helpless man, devoid of all degrees of honour, humanity, dignity and perfection, just because of a few meters of silk or woollen cloth, well tailored in a foreign style, and which might have been obtained through shameful and dishonourable bargains, looks down upon the servants of Allah with scorn, arrogance and haughtiness, devaluating the people. This is caused only by a completely powerless soul with so small a capacity that it takes the spit of a worm or the apparel of a sheep to be a cause of honour and dignity for itself.
O helpless man! How wretched and indigent you are! You should be the pride of the world of possibility, and the gist of space and place. You are the offspring of Adam, and you should teach the names and the attributes. You are the child of the (Allah's) successor; so, you should be of the brilliant signs (of Allah). "A whistle calls you from the turret of the 'Arsh".  You, unfortunate degenerate! You have usurped a handful of remnants and apparels of helpless animals, by which you take pride. This pride of yours is that of a silk worm, a sheep, a camel, a squirrel or a fox. Why do you feel proud of others' clothes, and show arrogance by others' pride?
In short, as the quality, the value and the decoration of the clothes have their effects on the souls, Imam Amirul Mu'minin (AS), as quoted by the late Qutb the Rowandi, said: "Whoever wears luxurious clothes, he will be, inevitably, arrogant, and the Fire is inevitably for the arrogant."  There are effects in their fashion and tailoring. It sometimes happens that the one who wears the clothes cut similar to those of the foreigners, gets a feeling of ignorant attachment to them, and thus, he repulses and abominates the friends of Allah and His Messenger, and loves their enemies. In this respect, Imam as Sadiq (AS) is quoted to have said: "Allah, the Exalted and Most High, inspired one of the prophets commanding him: 'Tell the believers not to wear the clothes of My enemies, not to eat like My enemies, and not to walk like My enemies, so as not to be My enemies as they are My enemies."' 
As the too luxurious clothes affect the souls, similarly, too low and shabby clothes, both in material and quality, also affect them. It is most probably that this is more corruptive, by many degrees, than the exquisite clothes, as the soul can have quite crafty plots. When one sees himself distinguished from others by wearing rough, denim clothes, while others wear fine, soft clothes, he tries, as he loves himself, to neglect his defects, regarding this accidental and irrelevant affair as a matter of pride. He may probably get to admire himself and look down at the servants of Allah, alleging that the others are out of Allah's holy sanctum, thinking himself to be among the most sincere and favourite servants of Allah. It is also most probable that he will be afflicted with hypocrisy and other big corruptions. So wretched he is that, out of all the degrees of knowledge, taqwa and spiritual perfections, he suffices himself with rough, shabby wears, unaware of thousands of his big faults, the biggest of which is this very bad effect resulting from these clothes. He thinks himself, who is of Satan's friends, of the people of Allah, regarding the servants of Allah as nothing and worthless. It also happens that the style and the way he wears his clothes throw him into many mischiefs, such as wearing them in such an arrangement as to make him famous as an ascetic and a holy man.
In short, to wear clothes for distinction, on either side of the extremities, is a matter which shakes the weak hearts, and deprives them from good moralities, and causes conceit, hypocrisy, arrogance and pride, each one of which is a mother of spiritual vileness. They further lead to being attached to this world and loving it, which is the head of all sins and the source of all evils. Many hadiths also refer to many of the said affairs, as is stated in the noble al-Kafi, quoting Imam as Sadiq (AS), saying: "Allah, the Exalted, becomes angry with one's getting famous through clothes". 
He is also quoted to have said: "The famous, good or bad, is in the Fire." 
He is further quoted to have said: "Allah becomes angry with two fames: the fame of clothes and the fame of the salat." 
A hadith is quoted from the Messenger of Allah (SA), saying: "Whoever wears an apparel of fame, Allah will make him wear, in the Hereafter, an apparel of humility." 
. My leg is lame, while the destination is so far, My hand is short, while the dates are (high) on the date-palms. (by Hafiz Shirazi).
. Refer to footnote No.21.
. Refer to footnote No.96.
. Mustadrakul Wasa'il, "Book of as-Salat", chs. on "The Rules of the Clothes", ch. 16, Hadith 5, quoted from Lubbul Albab, Qutb the Rawandi.
. Al-Jawahirus-Saniyah, ch. on "Abu 'Abdullah Ja'far ibn Muhammad, as Sadiq", Hadith 60.
. Wasa'ilush-Shi'ah, vol. 3, p. 354, "Book of as Salat", chs. on "Rules Concerning the Clothes", ch. 12, Hadith 1.
. Ibid, Hadith 3.
. Mustadrakul Wasa'il, "Book of as Salat", chs. on "The Rules of the Clothes", ch. 8, Hadith 2.
. Ibid., Hadith 1.