SHAFAQNA – The scholars and seekers of the truth have been saying from the old days that: The issue of Imamate and Welayah is the heart of the religion, meaning a person who wants to find out about this issue, has moved from the surface/exterior and has discovered/identified the main point of the matter. And basically, the topic of Imamate and Welayah has been a main issue in Islam; meaning deep thinkers have become aware of it, and others have been invited to get to this depth; now, some get to this point and some do not [1].
[1] Imamat va Rahbari, Martyr Mortaza Motahhari (RA), Page 126.