Sri Ramana Maharishi

Sri Ramana Maharshi  explains SAMADHI  in the following way: 

(1) Holding on to Reality is samAdhi. 

(2) Holding on to Reality with effort is savikalpa samAdhi.
(3) Merging in Reality and remaining unaware of the world is nirvikalpa samAdhi.
(4) Merging in Ignorance and remaining unaware of the world is sleep.
(5) Remaining in the primal, pure natural state without effort is sahaja nirvikalpa samAdhi. 
(from "Talk 391") 

He further explains what He means by the difference between (3) and (5) in another talk: 

Even if one is immersed in nirvikalpa samAdhi for years together, when he emerges from it he will find himself in the environment which he is bound to have. That is the reason for the AchArya emphasising sahaja samAdhi in preference to nirvikalpa samAdhi in his excellent work vivekachUDAmaNi. One should be in spontaneous samAdhi - that is, in one's pristine state - in the midst of every environment. (Talk 54) 

and again in Talk 187, Sri Ramana explains both (3) and (5) as nirvikalpa samAdhi, but the sahaja type alone is permanent: 

In sleep the mind is alive but merged in oblivion (see (4) above). - In kevala nirvikalpa samAdhi, the mind is alive but merged in light, like a bucket with rope lowered into a well, that can be drawn out again. - In sahaja nirvikalpa samAdhi, the mind is dead , resolved into the Self, like a river discharged into the ocean - its identity lost - and which can never be re-directed from the ocean, once discharged into it.
(Talk 187) 

Thus when the disciple asks, "Is loss of body-consciousness a perquisite to the attainment of sahaja samAdhi?" Sri Ramana replies: 

What is body-consciousness? Analyse it. There must be a body and consciousness limited to it which together make up body-consciousness. These must lie in another Consciousness which is absolute and unaffected. Hold it. That is samAdhi. It exists when there is no body-consciousness because it transcends the latter, it also exists when there is the body-consciousness. So it is always there. What does it matter whether body-consciousness is lost or retained? When lost it is internal samAdhi: when retained, it is external samAdhi. That is all. A person must remain in any of the six samAdhi-s so that sahaja samAdhi may be easy for him.
(Talk 406) 

Below, Sri Ramana refers to samAdhi, not as a state to be gained, as in some of the many different types but as our natural state. He also points out the importance of the waking state, which I believe was a query in another thread: 

Samadhi is one's natural state. It is the under-current in all the three states. This - that is, 'I' - is not in those states, but these states are in It. If we get samAdhi in our waking state that will persist in deep sleep also. The distinction between consciousness and unconsciousness belongs to the realm of mind, which is transcended by the state of the Real Self.

(Talk 136) 

By shravaNa, Knowledge dawns. That is the flame. By manana, the Knowledge is not allowed to vanish. Just as the flame is protected by a wind-screen, so the other thoughts are not allowed to overwhelm the right knowledge. By nididhyAsana, the flame is kept up to burn bright by trimming the wick. Whenever other thoughts arise, the mind is turned inward to the light of true knowledge. When this becomes natural, it is samAdhi. The enquiry "Who am I?" is the shravaNa. The ascertainment of the true import of 'I' is the manana. The practical application on each occasion is nididhyAsana. Being as 'I' is samAdhi.
(Talk 647) 

Eternal, unbroken, natural state is jnAna." 
(Talk 385)

Essence of Vedanta - Part 35

SAVIKALPA SAMADHI AND NIRVIKALPA SAMADHI

The ground floor represents the life of passion in the sense-universe. The first storey corresponds to Savikalpa Samadhi. The second storey is tantamount to Nirvikalpa Samadhi. The third storey represents the Sahajavastha or a Jivanmukta. 

The moving of a bullock cart can be compared to Savikalpa Samadhi. It stops. This is Nirvikalpa Samadhi. The bulls are detached. This is Sahajavastha. When the Yogi has reached the last perfect stage of meditation and Samadhi, the fire whereof burns surely all the residue of his actions, he at once gets Liberation (Jivanmukti) in this very life.

In Savikalpa Samadhi, there is Triputi or the triad- Dhyata (the meditator), Dhyana (meditation) and Dhyeya (object of meditation). 

In Nirvikalpa Samadhi, this Triputi vanishes (Triputirahita). Nirvikalpa means "free from all sorts of modifications and imaginations." The mind completely melts in Brahman. The happiness or bliss that you get in Savikalpa Samadhi is termed Rasasvada. 

(When ever a sadhaka shares with the author that he/ she is experiencing extreme bliss/ joy in mediation, the author asks the same question as Sri Ramana asks- " Who is the one who is experiencing Joy/ Bliss??. If it is not you, then you cannot experience it, if it is you, then transcend that identity also and then come and tell me what did you experience !!)

This is also an obstacle  for further spiritual progress. It makes you stop here. It cannot liberate you. You must further march onwards to attain the highest Nirvikalpa state wherein lies your whole freedom.

ADVANTAGES OF BHAKTI YOGA SADHANA

Devotion or Bhakti Yoga is  easy and safe. Any man can repeat the Name of God. Anyone can sing His praise. Without a mother, you cannot have a son. 

Even so, without Ananya Bhakti (one-pointed or single-minded devotion), you cannot have Jnana. When Bhakti is fully ripe, Brahma-Jnana dawns of itself, without much effort on the part of the Sadhaka.

Any Mantra is very powerful. It purifies the mind. It induces Vairagya. There is a spiritual current in all Mantras. A Mantra takes the devotee's soul first to one centre and then to another and so on, till access is gained to the goal or final region. 

Dhruva had Darshana of Lord Hari by repeating the Dvadasakshara (consisting of twelve letters) Mantra 'Om Namo Bhagavate Vasudevaya' given by Rishi Narada. 

Prahlada had Darshana of Mahavishnu by repeating the "Narayana" Mantra. 

Valmiki realised God by repeating "Mara-Mara" (which becomes Rama-Rama during the course of repetition). 

Tukaram of Maharashtra became one with Lord Krishna by chanting always "Vittala-Vittala," the name of the reputed image of Sri Krishna at Pandharpur.

CONTEMPLATION-FILLING-IDENTIFICATION

Mark the three processes that take place in the mind during meditation. These are: CONTEMPLATION, FILLING, IDENTIFICATION. This is another triplet. Remember these three word-images. Repeat them mentally while doing Sadhana. It will help you a lot really.

When the mind is withdrawn from the objects and deep reflection sets in, the objective consciousness is shut up; Savitarka Samadhi commences. 

When your meditation becomes deep, you generally operate through the subtle Karana Sarira only. 

The Karana-Sarira consciousness becomes your normal consciousness. Yogis have a normal Karana-Sarira consciousness. 

Bhaktas like Lord Gouranga, Tukaram, Tulsidas identified themselves with their Karana Sarira and had a normal Karana-Sarira consciousness. 

A Bhakta of Karana-Sarira consciousness is an occupant of Brahma Loka even when living in the fleshy tabernacle. 

He is one with Brahman or Hiranyagarbha. He has Divine Aisvarya; yet he has a thin ethereal body. 

He keeps up his individuality. A whirlpool is one with the whole mass of the water. It has a separate existence also. Similar is the case with the Bhakta who has a life with his Karana-Sarira in Isvara.

Continued.......