Video : Abdu'l Baha says all Baha'i activities must be aimed at gaining converts...

Abdul Baha asks Baha'is to :
Convey the Message! Attract the hearts! Sow the seeds! Teach the cause (Baha'ism) to those who do not know.... I enter all meetings, all churches, so that the Cause (Baha'ism) maybe spread. 

This is also worth reading :
http://bahaitexts.blogspot.com/2017/05/what-is-aim-of-all-bahai-activities.html