The Yoga Sūtras of Patañjali are sutras (aphorisms) compiled by Sage Patanjali, taking materials about yoga from older traditions.

Patañjali divided his Yoga Sutras into four chapters or books (Sanskrit pada), containing in all 196 aphorisms, divided as follows:

Samadhi Pada(51 sutras):
Samadhi refers to a blissful state where the yogi is absorbed into the One. Samadhi is the main technique the yogin learns by which to dive into the depths of the mind to achieve Kaivalya. The author describes yoga and then the nature and the means to attaining samādhi. This chapter contains the famous definitional verse: "Yogaś citta-vritti-nirodhaḥ" ("Yoga is the restraint of mental modifications").

Sadhana Pada (55 sutras):
Sadhana is the Sanskrit word for "practice" or "discipline". Here the author outlines two forms of Yoga: Kriya Yoga (Action Yoga) and Ashtanga Yoga (Eightfold or Eightlimbed Yoga).
Kriya Yoga is closely related to Karma Yoga, which is also expounded in Chapter 3 of the Bhagavad Gita, where Arjuna is encouraged by Krishna to act without attachment to the results or fruit of action and activity. It is the yoga of selfless action and service.
Ashtanga Yoga describes the eight limbs that together constitute Rāja Yoga.

Vibhuti Pada(56 sutras):
Vibhuti is the Sanskrit word for "power" or "manifestation". 'Supra-normal powers' (Sanskrit: siddhi) are acquired by the practice of yoga. Combined simultaneous practice of Dhāraṇā, Dhyana and Samādhi is referred to as Samyama, and is considered a tool of achieving various perfections, or Siddhis. The temptation of these powers should be avoided and the attention should be fixed only on liberation. The purpose of using samadhi is not to gain siddhis but to achieve Kaivalya. Siddhis are but distractions from Kaivalaya and are to be discouraged. Siddhis are but maya, or illusion.

Kaivalya Pada(34 sutras):
Kaivalya literally means "isolation", but as used in the Sutras stands for emancipation or liberation and is used interchangeably with moksha (liberation), which is the goal of yoga. The Kaivalya Pada describes the process of liberation and the reality of the transcendental ego.

Eight components of yoga:

1. Yamas:
Yamas are ethical rules and can be thought of as moral imperatives. The five yamas listed by Patañjali in Yogasūtra are:

  • Ahiṃsā (अहिंसा): Nonviolence, non-harming other living beings
  • Satya (सत्य): truthfulness, non-falsehood
  • Asteya (अस्तेय): non-stealing
  • Brahmacārya (ब्रह्मचर्य): chastity, marital fidelity or sexual restraint
  • Aparigraha (अपरिग्रहः): non-avarice, non-possessiveness

2. Niyama:
The second component of Patanjali's Yoga path is called niyama, which includes virtuous habits, behaviors and observances (the "dos"). Sadhana Pada Verse 32 lists the niyamas as:

  • Shaucha: purity, clearness of mind, speech and body
  • Santhoṣha: contentment, acceptance of others, acceptance of one's circumstances as they are in order to get past or change them, optimism for self.
  • Tapas: persistence, perseverance, austerity.
  • Svādhyāya: study of Vedas (see Sabda in epistemology section), study of self, self-reflection, introspection of self's thoughts, speeches and actions.
  • Īśvarapraṇidhāna: contemplation of the Ishvara (God/Supreme Being, Brahman, True Self, Unchanging Reality).

3. Āsana:
Asana is thus a posture that one can hold for a period of time, staying relaxed, steady, comfortable and motionless. Patanjali does not list any specific asana, except the terse suggestion, "posture one can hold with comfort and motionlessness".

4. Prāṇāyāma:
Prāṇāyāma is made out of two Sanskrit words prāṇa (प्राण, breath) and ayāma (आयाम, restraining, extending, stretching).

After a desired posture has been achieved, recommends the next limb of yoga, prāṇāyāma, which is the practice of consciously regulating breath (inhalation and exhalation). This is done in several ways, inhaling and then suspending exhalation for a period, exhaling and then suspending inhalation for a period, slowing the inhalation and exhalation, consciously changing the time/length of breath (deep, short breathing).

5. Pratyāhāra:
Pratyāhāra is a combination of two Sanskrit words prati- (the prefix प्रति-, "towards") and ahāra (आहार, "bring near, fetch").

Pratyahara is fetching and bringing near one's awareness and one's thoughts to within. It is a process of withdrawing one's thoughts from external objects, things, person, situation. It is turning one's attention to one's true Self, one's inner world, experiencing and examining self. It is a step of self extraction and abstraction. Pratyahara is not consciously closing one's eyes to the sensory world, it is consciously closing one's mind processes to the sensory world. Pratyahara empowers one to stop being controlled by the external world, fetch one's attention to seek self-knowledge and experience the freedom innate in one's inner world.

Pratyahara marks the transition of yoga experience from first four limbs that perfect external forms to last three limbs that perfect inner state, from outside to inside, from outer sphere of body to inner sphere of spirit.

6. Dhāraṇā:
Dharana (Sanskrit: धारणा) means concentration, introspective focus and one-pointedness of mind. The root of word is dhṛ (धृ), which has a meaning of "to hold, maintain, keep".

Dharana as the sixth limb of yoga, is holding one's mind onto a particular inner state, subject or topic of one's mind. The mind (not sensory organ) is fixed on a mantra, or one's breath/navel/tip of tongue/any place, or an object one wants to observe, or a concept/idea in one's mind. Fixing the mind means one-pointed focus, without drifting of mind, and without jumping from one topic to another.

7. Dhyāna:
Dhyana (Sanskrit: ध्यान) literally means "contemplation, reflection" and "profound, abstract meditation".

Dhyana is contemplating, reflecting on whatever Dharana has focused on. If in the sixth limb of yoga one focused on a personal deity, Dhyana is its contemplation. If the concentration was on one object, Dhyana is non-judgmental, non-presumptuous observation of that object. If the focus was on a concept/idea, Dhyana is contemplating that concept/idea in all its aspects, forms and consequences. Dhyana is uninterrupted train of thought, current of cognition, flow of awareness

8. Samādhi:
Samadhi (Sanskrit: समाधि) literally means "putting together, joining, combining with, union, harmonious whole, trance".

Samadhi is oneness with the subject of meditation. There is no distinction, during the eighth limb of yoga, between the actor of meditation, the act of meditation and the subject of meditation. Samadhi is that spiritual state when one's mind is so absorbed in whatever it is contemplating on, that the mind loses the sense of its own identity. The thinker, the thought process and the thought fuse with the subject of thought. There is only oneness, samadhi.

Samadhi is of two kinds, with and without support of an object of meditation:

1. Samprajnata Samadhi, also called savikalpa samadhi and Sabija Samadhi, meditation with support of an object.
Samprajata samadhi is associated with deliberation, reflection, bliss, and I-am-ness.
The first two associations, deliberation and reflection, form the basis of the various types of samapatti:
Savitarka, "deliberative": The citta is concentrated upon a gross object of meditation, an object with a manifest appearance that is perceptible to our senses, such as a flame of a lamp, the tip of the nose, or the image of a deity.[citation needed] Conceptualization (vikalpa) still takes place, in the form of perception, the word and the knowledge of the object of meditation. When the deliberation is ended this is called nirvitaka samadhi.

Savichara, "reflective": the citta is concentrated upon a subtle object of meditation, which is not percpetible to the senses, but arrived at through interference, such as the senses, the process of cognition, the mind, the I-am-ness, the chakras, the inner-breath (prana), the nadis, the intellect (buddhi). The stilling of reflection is called nirvichara samapatti.

2. Asamprajnata Samadhi, also called Nirvikalpa Samadhi and Nirbija Samadhi: meditation without an object, which leads to knowledge of purusha or consciousness, the subtlest element.