According to Osho, there is no rational 'why' for being a disciple or a master; it is an irrational, absurd love-affair with existence’s mystery. Seeking reasons only appeases the mind and kills the beautiful. Discipleship happens when an inexplicable longing arises; you respond by trusting, not by justifying. It’s participation in the unfathomable, beyond logic or utility.
You become a disciple not for a reason, but because your heart mysteriously falls in love with the unknown—so stop asking why and simply trust.