There are two classes of sannyāsīs, or persons in the renounced order of life. The Māyāvādī sannyāsīs are engaged in the study of Sāṅkhya philosophy, whereas the Vaiṣṇava sannyāsīs are engaged in the study of Bhāgavatam philosophy, which affords the proper commentary on the Vedānta-sūtras. The Māyāvādī sannyāsīs also study the Vedānta-sūtras, but use their own commentary, called Śārīraka-bhāṣya, written by Śaṅkarācārya. The students of the Bhāgavata school are engaged in the devotional service of the Lord, according to pāñcarātrikī regulations, and therefore the Vaiṣṇava sannyāsīs have multiple engagements in the transcendental service of the Lord. The Vaiṣṇava sannyāsīs have nothing to do with material activities, and yet they perform various activities in their devotional service to the Lord. But the Māyāvādī sannyāsīs, engaged in the studies of Sāṅkhya and Vedānta and speculation, cannot relish the transcendental service of the Lord. Because their studies become very tedious, they sometimes become tired of Brahman speculation, and thus they take shelter of the Bhāgavatam without proper understanding. Consequently their study of the Śrīmad-Bhāgavatam becomes troublesome. Dry speculations and impersonal interpretations by artificial means are all useless for the Māyāvādī sannyāsīs. The Vaiṣṇava sannyāsīs, who are engaged in devotional service, are happy in the discharge of their transcendental duties, and they have the guarantee of ultimate entrance into the kingdom of God. The Māyāvādī sannyāsīs sometimes fall down from the path of self-realization and again enter into material activities of a philanthropic and altruistic nature, which are nothing but material engagements. Therefore, the conclusion is that those who are engaged in Kṛṣṇa conscious activities are better situated than the sannyāsīs engaged in simple speculation about what is Brahman and what is not Brahman, although they too come to Kṛṣṇa consciousness, after many births.
(Bhagavad-Gita------5:6------purport).

There are different stages of devotional service and God realization. Strictly speaking, anyone who accepts the existence of God is situated in devotional service. To acknowledge that God is great is something, but not much. Lord Caitanya, preaching as an ācārya, a great teacher, taught that we can enter into a relationship with God and actually become God’s friend, parent or lover. In the Bhagavad-gītā Kṛṣṇa showed Arjuna His universal form because Arjuna was His very dear friend. Upon seeing Kṛṣṇa as the Lord of the universes, however, Arjuna asked Kṛṣṇa to forgive the familiarity of his friendship. Lord Caitanya goes beyond this point. Through Lord Caitanya we can become friends with Kṛṣṇa, and there will be no limit to this friendship. We can become friends of Kṛṣṇa not in awe or adoration but in complete freedom. We can even relate to God as His father or mother. This is the philosophy not only of the Caitanya-caritāmṛta but of Śrīmad Bhāgavatam as well. There are no other scriptures in the world in which God is treated as the son of a devotee. Usually God is seen as the almighty father who supplies the demands of His sons. The great devotees, however, sometimes treat God as a son in their execution of devotional service. The son demands, and the father and mother supply, and in supplying Kṛṣṇa the devotee becomes like a father or mother. Instead of taking from God, we give to God. It was in this relationship that Kṛṣṇa’s mother, Yaśodā, told the Lord, “Here, eat this or You’ll die. Eat nicely.” In this way Kṛṣṇa, although the proprietor of everything, depends on the mercy of His devotee. This is a uniquely high level of friendship, in which the devotee actually believes himself to be the father or mother of Kṛṣṇa.
(Sri Caitanya Caritamrta-------introduction).

There are different stages of devotional service and God realization. Strictly speaking, anyone who accepts the existence of God is situated in devotional service. To acknowledge that God is great is something, but not much. Caitanya, preaching as an ācārya, a great teacher, taught that we can enter into a relationship with God and actually become God's friend. In Bhagavad-gītā Kṛṣṇa showed Arjuna His universal form because Arjuna was His "very dear friend." Upon seeing Kṛṣṇa as the Lord of the universes, however, Arjuna actually asked Kṛṣṇa to forgive the familiarity of his friendship. Caitanya goes beyond this point. Through Lord Caitanya we can become friends with Kṛṣṇa, and there is no limit to this friendship. We can become friends of Kṛṣṇa not in awe or adoration but in complete freedom. We can even relate to God as His father. This is not only the philosophy of Caitanya-caritāmṛta but of Śrīmad Bhāgavatam as well. There are no other literatures in the world in which God is treated as the son of a devotee. Usually God is seen as the almighty Father who supplies the demands of His sons. The great devotees, however, sometimes treat God as a son in their execution of devotional service. The son demands, and the father supplies, and in supplying Kṛṣṇa the devotee becomes like a father. Instead of taking from God, we give to God. It was in this relationship that Kṛṣṇa's mother, Yaśodā, told the Lord, "Here, eat this or You'll die. Eat nicely." In this way Kṛṣṇa, although the proprietor of everything, depends on the mercy of His devotee. This is a uniquely high level of friendship in which the devotee actually believes himself to be the father of Kṛṣṇa.
(Teachings of Lord Caitanya).