For one who explains the supreme secret to the devotees, devotional service is guaranteed, and at the end he will come back to Me.
Generally it is advised that Bhagavad-gita be discussed amongst the devotees only, for those who are not devotees will neither understand Krishna nor Bhagavad-gita. Those who do not accept Krishna as He is and Bhagavad-gita as it is should not try to explain Bhagavad-gita whimsically and become offenders. Bhagavad-gita should be explained to persons who are ready to accept Krishna as the Supreme Personality of Godhead. It is a subject matter for the devotees only and not for philosophical speculators. Anyone, however, who tries sincerely to present Bhagavad-gita as it is will advance in devotional activities and reach the pure devotional state of life. As a result of such pure devotion, he is sure to go back home, back to Godhead.
(Bhagavad-gita As It Is 18.68 and Bhaktivedanta Purport)
There is no servant in this world more dear to Me than he, nor will there ever be one more dear.