BG 18.72

18.72 कच्चित् whether? एतत् this? श्रुतम् heard? पार्थ O son of Kunti (Arjuna)? त्वया by thee? एकाग्रेण onepointed? चेतसा by mind? कच्चित् whether? अज्ञानसंमोहः the delusion of ignorance? प्रनष्टः has been destroyed? ते thy? धनञ्जय O Dhananjaya.Commentary It is the duty of the spiritual teacher or preceptor to make the aspirant understand the teaching of the scripture and to enable him to attain the goal of life (Moksha). If the student has not grasped the subject he will have to explain it in some other way with similes? analogies and illustrations. That is the reason why Lord Krishna asks Arjuna Has the delusion of thy ignorance been destroyedThis What I have told thee.Have you heard it? O Arjuna? with onepointed mind Have you grasped My teachingDelusion of ignorance The absence of discrimination which is caused by ignorance and which is natural. The destruction of delusion is the aim of all this endeavour on your part to hear the scripture and the exertion on My part as the teacher.

— vedicscriptures · exposition · source ↗

The Lord was acting as the spiritual master of Arjuna. Therefore it was His duty to inquire from Arjuna whether he understood the whole Bhagavad-gītā in its proper perspective. If not, the Lord was ready to re-explain any point, or the whole Bhagavad-gītā if so required. Actually, anyone who hears Bhagavad-gītā from a bona fide spiritual master like Kṛṣṇa or His representative will find that all his ignorance is dispelled. Bhagavad-gītā is not an ordinary book written by a poet or fiction writer; it is spoken by the Supreme Personality of Godhead. Any person fortunate enough to hear these teachings from Kṛṣṇa or from His bona fide spiritual representative is sure to become a liberated person and get out of the darkness of ignorance.

— vedicscriptures · exposition · source ↗