Accepted as acarya
SB Canto 1
If he is conversant with the science of Kṛṣṇa, he can be accepted as an ācārya or guru, a spiritual master
SB 1.18.18, Purport: Suta Gosvami did not take his birth in a brahmana family. He was born in a family of mixed caste, or an uncultured low family. But because of higher association, like Sri Sukadeva Gosvami and the great rsis of Naimisaranya, certainly the disqualification of inferior birth was washed off. Lord Sri Caitanya Mahaprabhu followed this principle in pursuance of the Vedic usages, and by His transcendental association He elevated many lowborn, or those disqualified by birth or action, to the status of devotional service and established them in the position of acaryas, or authorities. He clearly stated that any man, whatever he may be, whether a brahmana or sudra by birth, or a householder or mendicant in the order of society, if he is conversant with the science of Krsna, he can be accepted as an acarya or guru, a spiritual master.
To be accepted as an ācārya among Indian transcendentalists who follow the Vedic principles, one must become a vastly learned scholar in Vedānta philosophy, either by studying it or hearing it
CC Adi 7.102, Purport: The Vaisnavas are by far the greatest philosophers in the world, and the greatest among them was Srila Jiva Gosvami Prabhu, whose philosophy was again presented less than four hundred years later by Srila Bhaktisiddhanta Sarasvati Thakura Maharaja. Therefore one must know very well that Vaisnava philosophers are not sentimentalists or cheap devotees like the sahajiyas. All the Vaisnava acaryas were vastly learned scholars who understood Vedanta philosophy fully, for unless one knows Vedanta philosophy he cannot be an acarya. To be accepted as an acarya among Indian transcendentalists who follow the Vedic principles, one must become a vastly learned scholar in Vedanta philosophy, either by studying it or hearing it.
Therefore, according to our Vedic system, the ācārya must understand Brahma-sūtra and explain. Then he'll be accepted as ācārya
Lecture on SB 3.25.4 -- Bombay, November 4, 1974: Generally, these Mayavadis give prominence of the comment given by Sankaracarya about Brahma-sutra, Sariraka-bhasya. But that is unnatural. The natural commentation is given by the author himself, Vyasadeva. So we have to understand... Vyasadeva has written Brahma-sutra, and we have to understand the meaning of Brahma... Brahma-sutra means codes only. So codes can be explained by the author himself. So our process is to accept the Brahma-sutra. Brahma-sutra-padais caiva hetumadbhir viniscitaih [Bg. 13.5]. Krsna says in the Bhagavad-gita. So Brahma-sutra is nyaya-prasthana. Nyaya-prasthana: very logically, transcendental knowledge. So brahma-sutra-padais caiva hetumadbhir viniscitaih [Bg. 13.5]. So we must... Therefore, according to our Vedic system, the acarya must understand Brahma-sutra and explain. Then he'll be accepted as acarya.
Sri Caitanya-caritamrta Lectures
So one must give an interpretation on the Vedānta philosophy; then he'll be accepted as ācārya. Three things: Vedānta philosophy, Bhagavad-gītā and Śrīmad-Bhāgavatam
Lecture on CC CC Madhya-lila 20.353-354 -- New York, December 26, 1966: Ultimately, the Mayavadi philosophers they say that God, the Supreme Absolute Truth, is impersonal, and the Vaisnava philosophers, they say in the ultimate end, the Absolute Truth is Person and He is, He is the Supreme Personality of Godhead, is Krsna. Krsnas tu bhagavan svayam [SB 1.3.28]. This is little difference, and they stick to their position and they fight. Fight means by philosophical arguments. That is going on since a very long time. But both of them belong to the sanatana Hindu dharma because both of them will talk on the Vedanta philosophy. They'll simply, they can give different interpretation, but they cannot say that "We don't accept Vedanta." Oh, that will..., then it is at once rejected. So one must give an interpretation on the Vedanta philosophy; then he'll be accepted as acarya. Three things: Vedanta philosophy, Bhagavad-gita and Srimad-Bhagavatam. One must be able to explain these three books. Then he'll be accepted acarya. These are the principles.