This letter, written to Muhammad Chetrî, states that the heart is important and that those worships done only as habits are useless.
May Allâhu ta'âlâ bless you with the lot of turning away from things other than Him and turning towards Him! The heart is essential. If the heart has fallen in love with anybody other than Allâhu ta'âlâ, it has been ruined; it is good for nothing. Unless the intention is sincere, beneficent deeds, help and worships done as a mere formality will be of no avail. It is also necessary for the heart to gain safety and not to be fond of anything besides Allâhu ta'âlâ. [That is, everything done should have been done because He commands or likes it. Anything which He dislikes should be avoided. Everything should be for His sake.] Both the heart's safety and the body's doing pious actions must be together. Unless the body does pious actions, it will be vain to say, "My heart is safe, [my heart is pure, look at my heart]." It will mean to deceive oneself. In this world, as there cannot be a soul without a body, so the heart cannot be pure unless the body worships and refrains from sins. Most of the irreligious and blasphemous people of our time do not worship and claim that their hearts have gained safety and that they even have kashfs. In this way, they deceive credulous Muslims. May Allâhu ta'âlâ, as an alms of His beloved Prophet 'alaihissalâtu wassalâmu wattahiyya', protect us all against believing such heretics! Âmîn.
[Things which Islam prohibits are vehement poisons. When Allâhu ta'âlâ created people, He commanded useful things and prohibited harmful things for them. He commanded, as absolutely necessary, those with definite uses. It became Fard to do them. And, of the things that are useful, those that are not so necessary became sunnat. Since it is absolutely necessary to cease from those which are definitely harmful, they became harâm. And it being not so necessary to refrain from some others, they became makrûh. It has been left to man's option to do or not to do some other actions; these became mubâh. If mubâhs are done with a goodwill, they will be given thawâb. If not done with a goodwill, they are sins.]