ya idaḿ paramaḿ guhyaḿ
mad-bhakteṣv abhidhāsyati
bhaktiḿ mayi parāḿ kṛtvā
mām evaiṣyaty asaḿśayaḥ

Translation of Bhagavad Gita 18.68

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 Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

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 Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

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).

Commentary by Sri Ramanuja of Sri Sampradaya:

18.69 There never exists nor has existed anyone other than such a person as described, who does greater service to Me than he. In the future too, there will not be another such. The first reference is to those who are not worthy to hear the Gita. It is meant to teach that explaining it to them is more displeasing to the Lord than not teaching to those who are worthy.

Commentary by Sri Sridhara Swami of Rudra Sampradaya:

Continuing further Lord Krishna confirms that there is no human more pleasing or dearer to Him any where in creation which according to the Bhagavat Purana comprises 400,000 species of human beings; then the devotee of His who reveals Srimad Bhagavad-Gita to His devotees. Nor will there be anyone more dear or pleasing to Him in the future.

Commentary by Sri Madhvacharya of Brahma Sampradaya:

Sri Madhvacharya did not comment on this sloka.

Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

Lord Krishna now reveals why one who serves Him in the previous way certainly attains communion with Him and that is because among all the 400,000 species of human beings in the material creation as confirmed in Srimad Bhagavatam none is more exalted and dear to Lord Krishna then the devotee who imparts the knowledge of Srimad Bhagavad-Gita to His devotees and none will ever be more exalted and dear to Him in the future.

Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

18.68 Yah, he who; abhi-dhasyati, will speak of, i.e., will present with the help of the text and its meaning, as I have done to you; imam, this; paramam, highest-that which has Liberation as its purpose; guhyam, secret, as spoken of above-(i.e.) the text in the form of a conversation between Kesava and Arjuna; madbhaktesu, to My devotees-. How will present? This is being stated: Krtva, entertaining; param, supreme; bhaktim, devotion; mayi, to Me, i.e., entertainting an idea thus-‘A service is being rendered by me to the Lord who is the supreme Teacher’-. Tho him comes this result: esyati, he will reach; mam, Me; eva, alone. He is certainly freed. No doubt should be entertained in this regard. By the repetition of (the word) bhakti (devotion) [In the word madbhaktesu.], it is understood that one becomes fit for being taught (this) Scripture by virtue of devotion alone to Him. Besides,

Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:

18.69 Ca, and; tasmat, as compared with him, with the one who hands down the Scripture; na kascit, none else; manusyesu, among human beings; is priya-krt-tamah, the best accomplisher of what is dear; me, to Me, i.e., among the present human beings, surely none else other than him exists who is a better accomplisher of what I cherish. Moreover, na bhavita, nor will there be in future; anyah, anyone else, a second person; bhuvi, in he world, here; priyatarah, dearer; tasmat, than him. [It may be argued that, since for a seeker of Liberation meditation is the best means for It, therefore he will have no inclination to transmit scriptural teachings. To this the Lord’s answer is: One longing for Liberation has a duty to impart this scriptural teaching to one possessing the aforesaid qualities.]

Sanskrit Shloka Without Transliteration Marks:

ya idam paramam guhyam
mad-bhaktesv abhidhasyati
bhaktim mayi param krtva
mam evaisyaty asamsayah

Sanskrit to English Word for Word Meanings:

yaḥ — anyone who; idam — this; paramam — most; guhyam — confidential secret; mat — of Mine; bhakteṣu — amongst devotees; abhidhāsyati — explains; bhaktim — devotional service; mayi — unto Me; parām — transcendental; kṛtvā — doing; mām — unto Me; eva — certainly; eṣyati — comes; asaḿśayaḥ — without doubt.