The four principles of the Vaiṣṇava philosophic doctrine are śuddha-advaita (purified oneness), dvaita-advaita (simultaneous oneness and difference), viśiṣṭa-advaita and dvaita. All four principles of Vaiṣṇava philosophy are based on the thesis of Śrīmad-Bhāgavatam explained in these two verses.
(Srimad Bhagavatam------3:28:41------purport).

Lord Caitanya advised, asat-saṅga-tyāga: one should avoid persons who are attached to the temporary. Asat is one who is too materially attached, who is not a devotee of the Lord and who is too attached to women or enjoyable material things. Such a person, according to Vaiṣṇava philosophy, is a persona non grata.
(Srimad Bhagavatam------3:29:18------purport).

Sometimes the spiritual master is addressed as Prabhupāda. Prabhu means "the Supreme Personality of Godhead," and pāda means "post." According to Vaiṣṇava philosophy, the spiritual master occupies the post of the Supreme Personality of Godhead, or in other words he is the bona fide representative of the Supreme Lord.
(Srimad Bhagavatam------4:8:69------purport).

The Vaiṣṇava philosophy in the process of Kṛṣṇa consciousness prohibits the devotee from all kinds of material aspirations. A Vaiṣṇava devotee should always be anyābhilāṣitā-śūnya, free from all material aspirations for the results of fruitive activities or empiric philosophical speculation.
(Srimad Bhagavatam------4:9:31------purport).

Kṛṣṇa claims in Bhagavad-gītā to be the father of all species of living entities; consequently the devotee of Kṛṣṇa is always a friend of all. This is called ahiṁsā. Such nonviolence can be practiced only when we follow in the footsteps of great ācāryas. Therefore, according to our Vaiṣṇava philosophy, we have to follow the great ācāryas of the four sampradāyas, or disciplic successions.
(Srimad Bhagavatam------4:22:24------purport).

The Lord is always transcendental to the material manifestation, even though it appears that the Lord and the material manifestation are one and the same. According to the Vaiṣṇava philosophy, He is one and different simultaneously. The material energy is a manifestation of His external potency, and since the potency is identical with the potent, it appears that the Lord and individual soul are one; but actually the individual soul is under the influence of material energy, and the Lord is always transcendental to it.
(Srimad Bhagavatam------4:22:38------purport).

The current Brahma-sampradāya is known as the Madhva-Gauḍīya-sampradāya. Even though Lord Śiva appeared to preach Māyāvāda philosophy, at the end of his pastime in the form of Śaṅkarācārya, he preached the Vaiṣṇava philosophy: bhaja govindaṁ bhaja govindaṁ bhaja govindaṁ mūḍha-mate. He stressed worshiping Lord Kṛṣṇa, or Govinda, three times in this verse and especially warned his followers that they could not possibly achieve deliverance, or mukti, simply by word jugglery and grammatical puzzles. If one is actually serious to attain mukti, he must worship Lord Kṛṣṇa. That is Śrīpāda Śaṅkarācārya's last instruction.
(Srimad Bhagavatam------4:24:18------purport).

The Supreme Lord is always independent, but because the living entities are not independent—due to their false idea of becoming independently happy—the material energy is troublesome. Consequently the material energy creates differentiation. Because the Māyāvādī philosophers cannot understand this, they want to be relieved from the material energy. However, because a Vaiṣṇava philosopher is in full knowledge of the Supreme Personality of Godhead, he finds no disturbance even in the material energy. This is because he knows how to utilize the material energy for the service of the Lord.
(Srimad Bhagavatam------4:24:61------purport).

This śloka explains that in relation to the material body even the factual truth cannot exist without a touch of untruth. The Māyāvādīs say, brahma satyaṁ jagan mithyā: "The spirit soul is truth, and the external energy is untruth." The Vaiṣṇava philosophers, however, do not agree with the Māyāvāda philosophy. Even if for the sake of argument the material world is accepted as untruth, the living entity entangled in the illusory energy cannot come out of it without the help of the body. Without the help of the body, one cannot follow a system of religion, nor can one speculate on philosophical perfection. Therefore, the flower and fruit (puṣpa-phalam) have to be obtained as a result of the body. Without the help of the body, that fruit cannot be gained. The Vaiṣṇava philosophy therefore recommends yukta-vairāgya. It is not that all attention should be diverted for the maintenance of the body, but at the same time one's bodily maintenance should not be neglected. As long as the body exists one can thoroughly study the Vedic instructions, and thus at the end of life one can achieve perfection.
(Srimad Bhagavatam------8:19:39------purport).

In Vaiṣṇava philosophy there are three ways for perfection—namely sādhana-siddha, perfection attained by executing devotional service according to the rules and regulations, nitya-siddha, eternal perfection attained by never forgetting Kṛṣṇa at any time, and kṛpā-siddha, perfection attained by the mercy of the spiritual master or another Vaiṣṇava. Kavirāja Gosvāmī here stresses kṛpā-siddha, perfection by the mercy of superior authorities. This mercy does not depend on the qualifications of a devotee. By such mercy, even if a devotee is dumb he can speak or write to glorify the Lord splendidly, even if lame he can cross mountains, and even if blind he can see the stars in the sky.
(Sri Caitanya Caritamrta------1:8:5------purport).

Kṛṣṇa's accepting the part of the gopīs is certainly contradictory according to any mundane calculations, but the Lord, by His inconceivable character, may act like the gopīs and feel separation from Kṛṣṇa, although He is Kṛṣṇa Himself. Such a contradiction can be reconciled only in the Supreme Personality of Godhead because He has energy that is inconceivable (acintya), which can make possible that which is impossible to do (aghaṭa-ghaṭana-patīyasī). Such contradictions are very difficult to understand unless a devotee strictly follows the Vaiṣṇava philosophy under the direction of the Gosvāmīs.
(Sri Caitanya Caritamrta------1:17:304------purport).

It is not that Rādhārāṇī is separate from Kṛṣṇa. Rādhārāṇī is also Kṛṣṇa, for there is no difference between the energy and the energetic. Without energy, there is no meaning to the energetic, and without the energetic, there is no energy. Similarly, without Rādhā there is no meaning to Kṛṣṇa, and without Kṛṣṇa, there is no meaning to Rādhā. Because of this, the Vaiṣṇava philosophy first of all pays obeisances to and worships the internal pleasure potency of the Supreme Lord. Thus the Lord and His potency are always referred to as Rādhā-Kṛṣṇa.
(Teachings of Lord Caitanya).

The ecstasy of transcendental love has two components—the context and the cause of the excitement. The context is also divided into two parts—the subject and the object. The exchange of devotional service is the subject, and Kṛṣṇa is the object. The transcendental qualities are the causes of excitement. This means that the transcendental qualities of Kṛṣṇa excite the devotee to serve Him. The impersonal (Māyāvādī) philosophers say that the Absolute Truth has no specific qualities, but the Vaiṣṇava philosophers say that the Absolute Truth is described as nirguṇa (without qualities) because He has no material qualities.
(Teachings of Lord Caitanya).

One should not neglect to offer due respect to the demigods. One may not be a devotee of demigods, but that does not mean that he should be disrespectful to them. For example, a Vaiṣṇava is not a devotee of Lord Śiva or Lord Brahmā, but he is duty-bound to offer all respects to such highly positioned demigods. According to Vaiṣṇava philosophy, one should offer respect even to an ant, so then what is there to speak of such exalted persons as Lord Śiva and Lord Brahmā?
(Nectar of Devotion).

The highest welfare activity for living entities is the preaching of Kṛṣṇa consciousness. It is stated herein that those who are specifically favored by the Lord can become absolutely Kṛṣṇa conscious and be engaged in the work of preaching the Vaiṣṇava philosophy.
(Krsna Book).

On hearing these statements of Mahārāja Parīkṣit's, Śukadeva Gosvāmī was overwhelmed with devotional ecstasy because of King Parīkṣit's advanced understanding of theVaiṣṇava philosophy. Śukadeva Gosvāmī was already engaged in describing the activities of the Lord, and when asked by Mahārāja Parīkṣit to describe them further, he continued to narrate Śrīmad-Bhāgavatam with great pleasure.
(Krsna Book).

The material world was created for the enjoyment of living entities who wanted to give up the eternal service of the Lord to become the supreme enjoyer themselves. According to Vaiṣṇava philosophy, when a living entity desires to gratify his senses and forgets the service of the Lord, he is given a place in the material world to act freely according to his desire, and therefore he creates a condition of life in which he either enjoys or suffers.
(Krsna Book).

The Lord is ever-existing, and the energies are ever-existing. Some of the energy is temporary—sometimes manifested and sometimes unmanifested—but this does not mean that it is false. The example may be given that when a person is angry he does things which are different from his normal condition of life, but the fact that the mood of anger appears and disappears does not mean that the energy of anger is false. As such, the argument of the Māyāvādī philosophers that this world is false is not accepted by the Vaiṣṇava philosophers.
(Krsna Book).

When a thing is taken as fact but actually has no existence at all, it is called false. But if something is mistaken for something else that exists, that does not mean it is false. The Vaiṣṇava philosophers use a very appropriate example, comparing this material world to an earthen pot. When we see an earthen pot, it does not at once disappear and turn into something else. It may be temporary, but the earthen pot is taken into use for bringing water, and we continue to see it as an earthen pot. Therefore, although the earthen pot is temporary and different from the original earth, we cannot say that it is false. We should therefore conclude that the earthen pot and the entire earth are both truths because one is the product of the other.
(Krsna Book).