Hazrat Moulana Ashraf Ali Thanwi (rahmatullahi ‘alaih) mentioned:

“At present, the best occupation is that of imparting deeni ‘ilm, especially for the one who has been endowed with ‘ilm. This is the need of the time. The virtue of it is also so great that perhaps no other ‘amal is equivalent to it in virtue. As long as the knowledge which a person imparted continues to be practised and imparted, rewards will continue accumulating in his book of deeds.” (Tuhfatul-Ulama, vol. 1, p. 45)

Source: Ihyaauddeen.co.za