Acharya Prashant explains that determining the eligibility of a person can only be done through a test. Just as a magnet clearly distinguishes between iron and copper, one's own personality must act as a challenge or a 'question paper' to reveal the nature of others. If a volunteer remains indistinguishable from the crowd, they cannot attract the right people or filter out the ineligible. To effectively distribute spiritual literature, the volunteer's own being must reflect the essence and light of the books they are selling. People do not just buy a book; they are drawn to the authenticity and character of the person offering it.