The Patañjali system of yoga instructs one on how to control the functions of the body's air in a technical manner so that ultimately all the functions of the air within become favorable for purifying the soul of material attachment. According to this yoga system, pratyag-ātmā is the ultimate goal. This pratyag-ātmā is withdrawn from activities in matter. The senses interact with the sense objects, like the ear for hearing, eyes for seeing, nose for smelling, tongue for tasting, hand for touching, and all of them are thus engaged in activities outside the self. They are called the functions of the prāṇa-vāyu. The apāna-vāyu goes downwards, vyāna-vāyu acts to shrink and expand, samāna-vāyu adjusts equilibrium, udāna-vāyu goes upwards—and when one is enlightened, one engages all these in searching for self-realization.
(Bhagavad-Gita------4:27------purport).

In the words of the Bhāgavatam, svarūpeṇa vyavasthitiḥ: this is the "real life of the living entity." Māyā, or illusion, is the condition of spiritual life contaminated by material infection. Liberation from this material infection does not mean destruction of the original eternal position of the living entity. Patañjali also accepts this by his words kaivalyaṁ svarūpa-pratiṣṭhā vā citi-śaktir iti. This citi-śakti, or transcendental pleasure, is real life. This is confirmed in the Vedānta-sūtra (1.1.12) as ānanda-mayo 'bhyāsāt. This natural transcendental pleasure is the ultimate goal of yoga and is easily achieved by execution of devotional service, or bhakti-yoga.
(Bhagavad-Gita------6:20-23------purport).

The yoga system, as described in Śrīmad-Bhāgavatam and Bhagavad-gītā or as recommended in the Patañjali yoga process, is different from the nowadays—practiced haṭha-yoga as it is generally understood in the Western countries. Real yoga practice is to control the senses and, after such control is established, to concentrate the mind on the Nārāyaṇa form of the Supreme Personality of Godhead, Śrī Kṛṣṇa. Lord Kṛṣṇa is the original Personality of Godhead, and all the other Viṣṇu forms—with four hands decorated with conch, lotus, club and wheel—are plenary expansions of Kṛṣṇa.
(Srimad Bhagavatam------3:15:45------purport).

In the samādhi stage one can see the Supreme Personality of Godhead in His partial form as Paramātmā, or as He is. Samādhi is described in authoritative yoga scriptures, such as the Patañjali-sūtras, to be a transcendental pleasure. The yoga system described in the books of Patañjali is authoritative, and the modern so-called yogīs who have manufactured their own ways, not consulting the authorities, are simply ludicrous. The Patañjali yoga system is called aṣṭāṅga-yoga. Sometimes impersonalists pollute the Patañjali yoga system because they are monists. Patañjali describes that the soul is transcendentally pleased when he meets the Supersoul and sees Him. If the existence of the Supersoul and the individual is admitted, then the impersonalist theory of monism is nullified. Therefore some impersonalists and void philosophers twist the Patañjali system in their own way and pollute the whole yoga process.
(Srimad Bhagavatam------3:21:12------purport).

According to Patañjali, when one becomes free from all material desires he attains his real, transcendental situation, and realization of that stage is called spiritual power. In material activities a person engages in the modes of material nature. The aspirations of such people are (1) to be religious, (2) to be economically enriched, (3) to be able to gratify the senses and, at last, (4) to become one with the Supreme. According to the monists, when a yogī becomes one with the Supreme and loses his individual existence, he attains the highest stage, called kaivalya. But actually, the stage of realization of the Personality of Godhead is kaivalya. The oneness of understanding that the Supreme Lord is fully spiritual and that in full spiritual realization one can understand what He is—the Supreme Personality of Godhead—is called kaivalya, or, in the language of Patañjali, realization of spiritual power.
(Srimad Bhagavatam------3:21:12------purport).

As described in the Patañjali yoga system, pramāṇa-viparyaya-vikalpa-nidra-smṛtyaḥ. By intelligence only one can understand things as they are. By intelligence only can one understand whether or not he is the body. The study to determine whether one's identity is spiritual or material begins in doubt. When one is able to analyze his actual position, the false identification with the body is detected.
(Srimad Bhagavatam------3:26:30------purport).

According to the Brahma-saṁhitā (5.40), yasya prabhā prabhavato jagad-aṇḍa-koṭi: the material universes are generated from the bodily rays of the Supreme Personality of Godhead. Yogīs who follow the principles of Patañjali accept the personality of the Absolute Truth, but they want to merge into the transcendental body of the Supreme Lord. That is their desire. Being the greatest authority, the Supreme Lord can easily allow many millions of living entities to merge into His body. The origin of everything is the Supreme Personality of Godhead, Bhagavān, and His bodily effulgence is known as the brahmajyoti, Brahmaloka or Siddhaloka.
(Sri Caitanya Caritamrta------2:6:269------purport).

Following the eightfold path of Patañjali, the meditative yogīs gradually elevate themselves, mastering the different stages until they reach samādhi, or the state of absorption in the Supersoul. In their desire to reach perfection, they tolerate all sorts of adversities and sufferings and remain fixed on their goal. Ultimately they attain a state of consciousness that cannot be compared to anything in this material world.
(Renunciation through Wisdom).

According to Patañjali's system, mysticism means perfect control of the mental plane with its various fickle inclinations. According to Patañjali, the transcendental state is to become free from sensuous activities and to attain the stage of perfection perceptible purely by the spirit soul. In such a state, the attention of the mystic never deviates from that spiritual achievement. The eightfold material perfections—such as aṇimā, laghimā, prāpti, īśitā, vaśitā, prākāmya, and so on—are concomitant in the attainment of perfection in mysticism, and are but indirect by-products of that process.
(Message of Godhead).