We have to calculate in the Fourth Chapter that the Lord says that, "I spoke to the sun-god, and sun-god spoke it to Manu, and Manu spoke to Ikṣvāku." And the next verse He says, evaṁ paramparā-prāptam imaṁ rājarṣayo viduḥ (BG 4.2): "So this confidential knowledge of Bhagavad-gītā was received in such disciplic succession." Disciplic succession. Just like the Lord Kṛṣṇa said to the sun-god, and the sun-god said to Manu, and Manu said to Ikṣvāku, and He summarizes that evaṁ paramparā-prāptam: "In such disciplic succession, the knowledge of Bhagavad-gītā was received."
Sa kāleneha mahatā yogo naṣṭaḥ parantapa. Now, He says that "This yoga . . . " This Bhagavad-gītā is also called yoga. Karma-yoga, jñāna-yoga, bhakti-yoga. You'll find in Bhagavad-gītā different yogas. So the whole book is called yoga. Now, here also it is stated, sa kāleneha mahatā yogo naṣṭaḥ parantapa: "My dear Arjuna, oh, you are the great hero. Now, that Bhagavad-gītā, the instruction which I imparted to the sun-god, was coming by disciplic succession, now it is lost."
Now, we have to note down this point. Why it is lost? Why it is lost? Do you think that there was no learned man during that time? During Kṛṣṇa's time? Oh, there are many learned sages. Not only one, two; there are dozens of learned sages. But still, the Lord says, Kṛṣṇa says, that "They . . . that knowledge which I exactly imparted to sun-god is now lost." How it is lost? There were many scholars, and still, how it is lost? The lost means that the purport of Bhagavad-gītā is lost.
Because scholars, they can interpret in their own way about Bhagavad-gītā, but that is not Bhagavad-gītā. That is not Bhagavad-gītā. That is the purpose which Kṛṣṇa wants to stress. So any student of Bhagavad-gītā must note it, that Bhagavad-gītā commented by a person—he may be very scholar in the material sense, but that scholarship will not help to comment on the Bhagavad-gītā.