In this connection, Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura comments that Advaita Ācārya took initiation from Mādhavendra Purī, who was a sannyāsī in the disciplic succession of the Madhva-sampradāya. According to Śrī Caitanya Mahāprabhu:

kibā vipra kibā nyāsī śūdra kene naya,
yei kṛṣṇa-tattva-vettā, sei ‘guru’ haya

“A person may be a brāhmaṇa, a sannyāsī, a śūdra or whatever, but if he is well conversant in the science of Kṛṣṇa, he can become a guru.” (Cc. Madhya 8.128) This statement is supported by Śrī Mādhavendra Purī. According to the pañcarātra injunction, only a householder brāhmaṇa can initiate. Others cannot. When a person is initiated, it is assumed that he has become a brāhmaṇa; without being initiated by a proper brāhmaṇa, one cannot be converted into a brāhmaṇa. In other words, unless one is a brāhmaṇa, he cannot make another a brāhmaṇa. A gṛhastha-brāhmaṇa partaking of the varṇāśrama-dharma institution can secure various types of paraphernalia to worship Lord Viṣṇu through his honest labor. Actually, people beg to be initiated by these householder brāhmaṇas just to become successful in the varṇāśrama institution or to become free from material desires. It is therefore necessary for a spiritual master in the gṛhastha-āśrama to be a strict Vaiṣṇava. A spiritual master from the sannyāsa order has very little opportunity to perform arcana, Deity worship, but when one accepts a spiritual master from the transcendental sannyāsīs, the principle of Deity worship is not at all neglected. To implement this conclusion, Śrī Caitanya Mahāprabhu gave us His opinion in the verse kibā vipra kibā nyāsī, etc. This indicates that the Lord understood the weakness of society in its maintaining that only a gṛhastha-brāhmaṇa should be a spiritual master. Śrī Caitanya Mahāprabhu indicated that it does not matter whether the spiritual master is a gṛhastha (householder), a sannyāsī or even a śūdra. A spiritual master simply must be conversant in the essence of the śāstra; he must understand the Supreme Personality of Godhead. Only then can one become a spiritual master. Dīkṣā actually means initiating a disciple with transcendental knowledge by which he becomes freed from all material contamination.