Rishi Patañjali describes the state of yoga right at the beginning of his yogasutra (sūtra 1.2):
yogaś citta-vṛtti nirodhaḥ
Word meaning
yogaś (basic form: yoga) – the state of unity
citta – human consciousness, composed of sense-consciousness (manas), intelligence (buddhi) and ego-consciousness or ego (ahaṁkāra)
vṛtti – inclinations, likes and dislikes (of the mind)
nirodhaḥ (basic form: nirodha) – hindrance, oppression, restriction, annihilation
Translation
Yoga is the state in which the qualities and inclinations of the human mind are dissolved.
interpretation
This refers to the state of the yogi who has reached the goal of human life: transforming human consciousness into divine consciousness. For what remains when the inclinations of the human mind have disappeared? It remains the true identity, the individual divine soul or ātmā.
But it’s not just about understanding intellectually that the identity of a human being is the immortal divine soul, but about experiencing it. This experience is beyond imagination; the yogi can only experience it, not describe it. Only through years of serious practice of meditation can a sadhaka (practitioner) achieve this state – in this state of deepest meditation, a yogi attains the breathless state in which his breathing stops and his heart stops beating.
In fact, in deep meditation, both breathing and heartbeat slow down. On the physical level, meditation thus has a soothing, restorative effect on all bodily functions, especially the nervous system and the circulation.
In this deep meditation, the mind is completely free of thoughts, so the state does not result from a conscious effort, but involuntarily through the grace of God. It is a gift.
In the practice of kriya yoga, it is the exercise paravastha, in which this condition is sought. The word parāvasthā means the highest state (para = highest, avastā = state). The human mind dissolves in the divine spirit as a drop of water dissolves in the ocean.