The purpose of the Bhagavad-gita can be preached only when it is taken up by real devotees of Krishna the Personality of Godhead.
One of the real devotees of Krishna was Arjuna during the appearance of Lord Krishna and as such the parampara of the Bhagavad-gita, which was broken prior to the occurrence of the battle of Kuruksetra, was reestablished at the battlefield and Arjuna was authorized to understand the purpose of the Bhagavad-gita. We should not miss this important point if we are serious about preaching the gospel of the transcendental literature.