If you want to advance in knowledge, then you must worship the ācāryas. Otherwise, what knowledge you will get? You cannot get, manufacturing knowledge or getting knowledge from somebody who has manufactured knowledge. The knowledge must be received by paramparā, by paramparā, as Kṛṣṇa says.
Evaṁ paramparā-prāptam (BG 4.2), sa kāleneha yogo naṣṭaḥ parantapa. He again spoke the science of Bhagavad-gītā to Arjuna because the paramparā was broken. Sa kāleneha naṣṭaḥ. Otherwise there was no need of speaking Bhagavad-gītā to Arjuna. And why He selected Arjuna to understand Bhagavad-gītā? That is also explained. One may say that Arjuna was a gṛhastha, householder, and a politician and a soldier. Why Bhagavad-gītā was instructed to him? That is natural. He was not a vedāntī. He was not a brahmin. He was not a sannyāsī.
Why he was selected to understand Bhagavad-gītā? This should be . . . there should be inquiry. Generally, you understand that a vedāntī, a sannyāsī, a brahmin may know about spiritual knowledge, about God. No, that is not the fact. The fact is, as Kṛṣṇa says: bhakto 'si priyo 'si me rahasyaṁ hy etad uttamam (BG 4.3): "Because you are My devotee, because you are My dear friend, you can understand the mystery of Bhagavad-gītā."