verse 2.27

तस्य सप्तधा प्रान्तभूमिः प्रज्ञ ॥२७॥

tasya saptadhā prānta-bhūmiḥ prajña ॥27॥

Through this unbroken flow of discriminative awareness, one gains perfect knowledge which has seven spheres.

Verse 2.28

योगाङ्गानुष्ठानादशुद्धिक्षये ज्ञानदीप्तिराविवेकख्यातेः ॥२८॥

yoga-aṅga-anuṣṭhānād-aśuddhi-kṣaye jñāna-dīptir-āviveka-khyāteḥ ॥28॥

By dedicated practice of the various aspects of yoga impurities are destroyed: the crown of wisdom radiates in glory.

There are seven states to be integrated between the seen (prakrti) and the seer (purusha) . 

They are: integration of the body (sharira samyama) , the

senses (indriya samyama} , energy (prana samyama}, mind (mano samyama} , intellect (buddhi samyama}, consciousness (citta samyama) and soul (atma samyama} , each realizing its own individual identity. Steady in yoga will bring this sevenfold knowledge.

The seven states can also be correlated with the wakeful (jagrata) , dreamy (svapna), and sleepy (nidra) states, and the state of oneness with the Supreme Soul (turya) ; and the three intermediate states between them.

To simplify the meaning of this sutra for yoga practitioners, can be given another following interpretation: 

knowledge of the body (sharira jnana), knowledge of energy (prana jnana) , control of the mind (mano jnana) , stability in intelligence (vijnana jnana), knowledge gained by experience (anubhavika jnana), absorption of the various flavours that life offers (rasatmaka jnana), knowledge of the self (atma jnana) .

In other words, by yogic practices, the sadhaka conquers his body, controls his energy, restrains the movements of the mind and develops sound judgement, from which he acts rightly and becomes luminous. From this

luminosity he develops total awareness of the very core of his being, achieves supreme knowledge, and merges his self to the Supreme Soul, Paramatman.

Patanjali sums up the effects of yoga in this one sutra. He says that by regular and devoted practice, the impurities of the sadhaka's body and mind are consumed, the causes of afflictions removed and the crown of wisdom is acquired.

This wisdom and achievement keep the sadhaka innocent and free of pride.

Yoga can cure or lessen our physical, mental, moral and spiritual sufferings.

Perfection and success are certain only if one practises with love and whole-hearted dedication.

PATANJALI YOGA SUTRAS