from any varna/asrama

It does not matter whether one is a brahmana, sudra, grhastha or sannyasi. These are all material designations. A spiritually advanced person has nothing to do with such designations. Therefore, if one is advanced in the science of Krsna consciousness, regardless of his position in human society, he may become a spiritual master. (More...)

"Whether one is a brahmana, a sannyasi or a sudra-regardless of what he is-he can become a spiritual master if he knows the science of Krsna." (Cc. Madhya 8.128) Anyone completely aware of the science of Krsna, regardless of his status in life, is a guru. Thus Prahlada Maharaja is a guru in all circumstances. (More...)

One who is actually advanced in spiritual knowledge of Krsna is never a sudra, even though he may have been born in a sudra family. However, if a vipra or a brahmana is very expert in the six brahminical activities (pathana, pathana, yajana, yajana, dana, pratigraha) and is also well versed in the Vedic hymns, he cannot become a spiritual master unless he is a Vaisnava. But if one is born in the family of candalas yet is well versed in Krsna consciousness, he can become a guru. These are the sastric injunctions, and strictly following these injunctions, Sri Caitanya Mahaprabhu, as a grhastha named Sri Visvambhara, was initiated by a sannyasi-guru named Isvara Puri. Similarly, Sri Nityananda Prabhu was initiated by Madhavendra Puri, a sannyasi. According to others, however, He was initiated by Laksmipati Tirtha. Advaita Acarya, although a grhastha, was initiated by Madhavendra Puri, and Sri Rasikananda, although born in a brahmana family, was initiated by Sri Syamananda Prabhu, who was not born in a caste brahmana family. There are many instances in which a born brahmana took initiation from a person who was not born in a brahmana family. The brahminical symptoms are explained in Srimad-Bhagavatam (7.11.35), wherein it is stated: (More...)

If a person is born in a sudra family but has all the qualities of a spiritual master, he should be accepted not only as a brahmana but as a qualified spiritual master also. This is also the instruction of Sri Caitanya Mahaprabhu. Srila Bhaktisiddhanta Thakura therefore introduced the sacred thread ceremony for all Vaisnavas according to the rules and regulations. (More...)

Srila Bhaktivinoda Thakura says in his Amrta-pravaha-bhasya that sannyasis in the line of Saṅkaracarya always think that they have performed all the duties of brahmanas and that, furthermore, having understood the essence of Vedanta-sutra and become sannyasis, they are the natural spiritual masters of all society. Similarly, persons born in brahmana families think that because they execute the ritualistic ceremonies recommended in the Vedas and follow the principles of smrti, they alone can become spiritual masters of society. These highly exalted brahmanas think that unless one is born in a brahmana family, one cannot become a spiritual master and teach the Absolute Truth. To cut down the pride of these birthright brahmanas and Mayavadi sannyasis, Sri Caitanya Mahaprabhu proved that a person like Ramananda Raya, although born in a sudra family and situated in the grhastha-asrama, can become the spiritual master of such exalted personalities as Himself and Pradyumna Misra. This is the principle of the Vaisnava cult, as evinced in the teachings of Sri Caitanya Mahaprabhu. A person who knows what is spiritual and what is material and who is firmly fixed in the spiritual position can be jagad-guru, the spiritual master of the entire world. One cannot become jagad-guru simply by advertising oneself as jagad-guru without knowing the essential principles for becoming jagad-guru. Even people who never see what a jagad-guru is and never talk with other people become puffed-up sannyasis and declare themselves jagad-gurus. Sri Caitanya Mahaprabhu did not like this. Any person who knows the science of Krsna and who is fully qualified in spiritual life can become jagad-guru. Thus Sri Caitanya Mahaprabhu personally took lessons from Sri Ramananda Raya and also sent Pradyumna Misra, an exalted brahmana, to take lessons from him. (More...)

So the reason is... [reading:] "According to Sri Caitanya Mahaprabhu, anyone who is conversant in the transcendental knowledge or the science of Godhead, be he a brahmana or sudra, a householder or a sannyasi, is eligible to become a spiritual master." Not that because he was born a sudra, he cannot preach, he cannot take the post of acarya or spiritual master. That is not Caitanya philosophy. Caitanya philosophy has nothing to do with this body, external body. Caitanya philosophy is concerned with the soul. This movement is the movement of elevating the soul, saving the soul from degradation. Therefore people sometimes are surprised. The bodily concept of life, the same activities will be karma. And on the platform of spiritual life, the same karma will be bhakti. Same karma will be bhakti. So bhakti is not inactivity. Bhakti is all active. Yat karosi yaj juhosi yad asnasi yat tapasyasi kurusva tad mad-arpanam [Bg 9.27]. This is bhakti, bhakti-yoga. Krsna says to everyone, "If you cannot give up your karma, then that's all right. But the result of your karma, give to Me. Then it will be bhakti." (More...)