Hadrat Imâm-i Rabbânî says in the 87th letter of the second volume of his Maktûbât:

In other words, each Muslim’s first duty is to obey the Sharî’at and refrain from the things which the Sharî’at dislikes, from the bid’ats.

If a person uncovers an abandoned, forgotten sunnat, he will get the thawâb of a hundred martyrs. Then, just imagine how much thawâb there is in resuscitating a fard or wâjib. Therefore, one should be careful about the ta’dîl-i arkân when performing namâz. In other words, at the rukû, at the sajda, at the qawma and at the jalsa, each limb should become motionless and remain so for a while; most of the savants of the Hanafî said that this was wâjib. Imâm-i Abû Yûsuf and Imâm-i Shâfi’î said that it was fard. The majority of Muslims have been neglecting this. A person who reveals this one deed will be given much more thawâb than that which is given to a hundred martyrs who have fought and given their lives in the way of Allah. This same rule applies to all the rules of the Sharî’at. That is, a person who teaches one of the halâls, harâms, makrûhs, fards, wâjibs and sunnats and has it obeyed will get the same amount of thawâb.

The forty-third verse of the famous book Qasîdat al-Amâlî  says, “The fard ’ibâdât are not included in îmân.” Hadrat al-Imâm al-a’zam Abu Hanîfa declared that deeds were not a part of îmân. ‘Îmân’ means ‘belief.’ There is neither paucity nor plentifulness in believing. If ’ibâdât were of îmân, îmân would increase or decrease. The belief will not be accepted after the curtain rises up from in front of the eyes and the torture is seen [at the moment one dies]. Those who pass away with îmân at that moment, when ’ibâdât cannot be performed, believe only by heart. And this is called “îmân” in the âyat. In many âyats, those who have îmân are ordered to perform ’ibâdât. Therefore, belief is separate from ’ibâdât. Furthermore, the Qur’ânic phrase “Those who believe and those who do pious deeds” shows that ’ibâdât and îmân are distinct. The âyat al-karîma, “Those who, being believers, do pious deeds...” shows clearly that deeds are separate from belief. For, stipulation must be different from what (who) is stipulated. It was said unanimously that anyone who, just after becoming a believer, died and found no time to perform any ’ibâda was a believer. It is declared in the Hadîth al-Jibrîl that îmân is only belief.