A Raja Yogi gets Nirodha-Samadhi through by restraining the mental modifications. A devotee gets Bhava-Samadhi through Love of the Lord. It is only the Raja Yogi who attempts the annihilation of the thought waves, the Nirodha Samadhi. A devotee sees God in all objects. He does not check the thought waves. He changes his mental attitude. It is the mind that creates all the differences and separateness. The world is all Bliss, only if you change your angle of vision, your mental attitude. You will find heaven on earth. You can bring down to normal objective consciousness a Raja Yogi or Bhakti Yogi or Jnana Yogi by mere shaking of the body or blowing a conch.
SAMADHI THROUGH HATHA YOGA
A Hatha Yogi draws all his Prana from the different parts of his body and takes it to the Sahasrara Chakra (thousand-petalled lotus) at the top of the head. Then he enters into Samadhi (super conscious state). Therefore it is very difficult to bring him down to objective consciousness by merely shaking his body. Hatha Yogis have remained buried underneath the earth in Samadhi for years together. They plug the posterior nostrils through Khechari Mudra (a king of Hatha Yogic Kriya) with their long tongues.
Prana and Apana that move in the chest and anus respectively are united by the Yogic processes of Jalandhara, Mula and Uddiyana Bandhas and the united Prana-Apana is driven into the Sushumna Nadi (central nerve) of the spinal canal. The Pranas, when thus driven, draw up the mind also along the Sushumna Nadi which is otherwise known as Brahma Nadi. During the ascent in the Sushumna Nadi, the three Granthis or knots, viz., Brahma-Granthi at Muladhara-Chakra, Vishnu-Granthi at Manipura-Chakra and Rudra-Granthi at Ajna-Chakra should be cut asunder by strenuous efforts. These knots prevent the ascent of Kundalini. Bhastrika Pranayama breaks down these knots. When Kula-Kundalini Sakti that lies dormant in the Muladhara-Chakra in the form of a coiled serpent with 3 1/2 curves or turns, with the face downwards is awakened by spiritual Practice, it ascends upwards towards Sahasrara Chakra or the thousand-petalled lotus in the crown of the head and takes along with it the mind and Prana also. When the mind is in the Sushumna, the Yogi is shut out from the objective, physical consciousness of the world. He is practically dead to the world, sees various visions and moves in the mental, ethereal space. Samadhi starts.
SAMADHI THROUGH RAJA YOGA
Deep meditation leads to Samadhi or oneness with God. If you can fix the mind for ten seconds steadily on a particular object, it is concentration. Ten such concentration become meditation. Ten such meditation form a Samadhi. The mind is filled with Soul or God. Mind loses its own consciousness and becomes identified with the object of meditation. Just as a toy made of salt melts in water, even so, the mind melts in Brahman in Nirvikalpa Samadhi. A sudden stroke of mystic illumination puts an end to all the empirical existence altogether and the very idea or remembrance of such a thing as this world or the narrow individuality of the spirit in this world absolutely leaves the Self.
In trained Yogis, you cannot say where abstraction ends and concentration begins; where concentration ends and meditation begins; where meditation ends and Samadhi (super conscious state) begins. The moment they sit on the Asana, all the processes occur simultaneously with electric or lightning speed and they enter Samadhi at their conscious will. In the neophytes, abstraction first takes place. Then concentration begins. Then meditation slowly commences. Before Samadhi manifests, their minds, getting impatient and tired, drop down. Constant and intense practice, with light but nutritious food, will bring about sanguine success in getting Samadhi.
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 liberation of emodied Soul. The moving of a bullock cart can be compared to Savikalpa Samadhi. It stops. This is Nirvikalpa Samadhi. The bulls are detached. This is liberation. 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 Supreme. The happiness or bliss that you get in Savikalpa Samadhi is termed Rasasvada. 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.
Mind – Its Mysteries and Control by Sri Swami Sivananda