Throughout your lives, you should have the perpetual concern of how you will lead your lives in accordance to the knowledge of deen which you have learnt and are acquiring. This is the first right that you owe to the knowledge of deen.
Remember that the knowledge of deen is not merely a science, but rather, it is a complete way of life which has been brought to us by the Ambiyaa (‘alaihimus salaam). Rasulullah (sallallahu ‘alaihi wasallam) sought protection in Allah Ta‘ala from that knowledge which does not benefit one (and which does not motivate one towards righteousness).
Furthermore, you are well aware of the numerous severe warnings sounded in the Qur’aan and Ahaadith for the Ulamaa and learned who do not practise on their knowledge. You should also understand that the sin of an Aalim in regard to not practising on his knowledge is not confined to him not performing salaah, not fasting, drinking wine or committing zina, as these sins apply to all – Ulamaa and non-Ulamaa. Rather, the sin of not practising on his knowledge refers to him not practising on the knowledge he possesses and not fulfilling the rights of that knowledge (in all departments of his life).
In the Qur’aan Majeed, Allah Ta‘ala mentions that the Ulamaa of the Ahl-e-Kitaab (Jews and Christians) were cursed because they did not practise on their knowledge:
فَبِمَا نَقضِهم مِّیثَاقَهم لَعَنّٰهم وَجَعَلنَا قُلُوبَهم قٰسِیَة
Because of their breach of their pledge (of practicing on the Towrah), We cursed them, and made their hearts grow hard. (Surah Maa’idah v. 13)
(Malfoozaat Hazrat Moulana Muhammad Ilyaas (rahmatullahi ‘alaih) pg. 102-103)