Hazrat Moulana Muhammad Ilyaas (rahmatullahi ‘alaih) once mentioned the following:
In many Deeni madaaris, there is a serious shortcoming and weakness that is witnessed. The serious shortcoming and weakness that is witnessed is that although the students are educated regarding Deen, effort is not made upon them, that after they qualify, they should fulfil the purpose of them studying Deen i.e. serving Deen, spreading the sunnah and inviting people towards Allah Ta‘ala.
The result of not making this effort upon the students is that after they graduate, many students are not concerned about propagating and teaching Deen to the people. Rather, their only concern is to earn a livelihood. Thus, either they learn tibb (medicine) or they enrol in government universities so that they may acquire some degree and gain employment as teachers in English schools. In this manner, the time, money and effort that was spent in making them ‘Ulama is wasted, as there is no productivity found in Deen from them thereafter. In fact, at times, (due to such ‘Ulama studying in universities and subscribing to wrong values, etc.) they even begin to assist the enemies of Deen.
Therefore, merely teaching the students Deen is not sufficient. Rather, together with teaching them Deen, a concerted effort should be made to ensure that the students who graduate will practice Deen and remain in the service of Deen, thereby fulfilling the rights of the knowledge of Deen which they have acquired.
If one’s farm does not produce any crop, this will be regarded as a great loss. However, if crops are produced, but then they are used to benefit the enemy, then this indeed is an even greater loss.
(Malfoozaat Hazrat Moulana Muhammad Ilyaas (rahmatullahi ‘alaih) pg. 15)