Hazrat Moulana Muhammad Ilyaas (rahmatullahi ‘alaih) once mentioned the following:
The primary purpose and goal of our effort of Da’wat and Tableegh is to teach people the complete deen that was brought by Rasulullah (sallallahu ‘alaihi wasallam) (in other words, to bring the ummah upon the complete teachings of Islam). This is our actual purpose and goal.
As for sending jamaats to different areas and encouraging people to make gusht in their localities, then these are various means adopted to achieve the primary purpose and goal of connecting people to deen. Similarly, teaching people the kalimah (i.e. imaan) and how to perform salaah can be regarded as the fundamentals of this effort of Da’wat and Tableegh.
It is obvious that the jamaats which go out (in the path of Allah Ta‘ala) cannot attend to every deeni responsibility. Rather, the most that they can do is upon arriving in any locality, they should try their best to create a deeni awakening and awareness among the people of the locality and revive the concern for deen within them. Similarly, they should make an effort on those who are far from deen and try to link them to the ulama and pious people living in the locality. Likewise, they will encourage those people of the locality who have the concern of deen at heart to make an effort on the people of their locality.
(Malfoozaat Hazrat Moulana Muhammad Ilyaas (rahmatullahi ‘alaih) pg. 26)