ya idam paramam guhyam mad-bhaktesv abhidhasyati bhaktim mayi param kritva mam evaishyaty asamsayah
Translation
For one who explains this supreme secret to the devotees, pure devotional service is guaranteed, and at the end he will come back to Me.
Commentary by Srila Prabhupada
Generally it is advised that Bhagavad-gita be discussed amongst the devotees only, for those who are not devotees will understand neither 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.
Commentary by Sri Visvanatha Cakravarti Thakur
This verse and the next state the results of giving instructions of bhakti. The instructor first attains parama bhakti (param bhaktim) and then the Lord himself (mam eva esyati).
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