Generally when you have dreamless or deep sound sleep it is either you do not remember what you dreamt of or you fall into absolute unconsciousness which is almost death-a taste of death. But there is the possibility of a sleep in which you enter into an absolute silence, immortality and peace in all parts of your being and your consciousness merges into Sat-Chit-Ananda. You can hardly call it sleep for there is perfect awareness. In that condition you can remain for a few minutes. It will give you more rest and refreshment than hours of ordinary sleep. You cannot have it by chance. It requires a long training.
When your meditation becomes deep, you generally operate through the subtle Karana Sarira (causal body) only. The Karana Sarira consciousness becomes your normal consciousness. Yogins have a normal Karana Sarira consciousness. Bhaktas like Lord Gauranga, Tukaram, Tulasidas, identified themselves with their Karana Sarira and had normal Karana Sarira consciousness. A Bhakta too becomes one with Brahman. He has divine Aisvarya yet he has a thin ethereal body. He keeps up his individuality. A whirl-pool 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.
You will have to pass through six stages of meditation and finally you will enter into perfect Nirvikalpa Samadhi or superconscious State. Form-perception and reflex-perception will totally vanish. There is neither meditation nor the meditated now. The meditator and the meditated have become one. You will attain now the highest knowledge, eternal and supreme peace. This is the aim of existence. This is the final beatitude of life. You are an established sage or an illumined Jivanmukta now. You are liberated while living. Hence you are called a Jivanmukta. You are absolutely free from pain, sorrow, fear, doubt and delusion. You have become identical with Brahman. The bubble has become the ocean. The river has joined the ocean, and has become the ocean. All differences and distractions will totally vanish. You will experience "I am the Immortal Self. All indeed is Brahman. There is nothing but Brahman."
In the beginning of meditation lights of various colours, such as red, white, blue, green, a mixture of red and green light, etc., appear in the forehead. They are Tanmatric lights. Every Tattva has its own hue. Prithvi Tattva has yellow colour. Apas has white colour. Agni has red colour. Vayu has green colour. Akasa has blue colour. The coloured lights are due to these Tattvas.
Sometimes a big sun or moon or lightning-like flashes appear in front of the forehead during meditation. Do not mind these appearances. Shun them. Try to dive deep into the source of these lights.
Sometimes Devatas, Rishis, Nitya Siddhas will appear in meditation. Receive them with honour. Bow to them. Get advice from them. They appear before you to help and give you encouragement.
When there is one Vritti alone, you will get Savikalpa Samadhi. When this one Vritti also dies, you will get Nirvikalpa Samadhi.
In Samadhi, the Triputi (triad-knower, knowledge and knowable) vanishes. The meditator and the meditated, the thinker and the thought become one and identical. There is no meditation in Samadhi. It drops. The Dhyata (meditator) and Dhyana get merged in Dhyeya (object of meditation).
Beginners will get jerks in meditation. Jerks of head, feet, hands, arms, forearm and trunk may take place. Timid persons are unnecessarily alarmed on the score. It is nothing. Meditation brings on changes in the cells of brain, nerves, etc. Old cells are replaced by new vigorous cells. They are filled with Sattva. New groups, new channels for Sattvic thought-currents, new avenues are formed in the brain and mind. The muscles are therefore agitated a bit. Be courageous and bold. Courage is an important virtue and qualification for aspirants. Cultivate this positive quality.
For a few days probably there will be no change perceptible. You will still feel and show irritability. Go on practising every morning. Presently, as you say an irritable thing, the thought will flash into your mind, unbidden, "I should have been patient." Still go on with your practice. Soon the thought of patience will arise with the irritable impulse and the outer manifestation will be checked. Still go on practising. The irritability has disappeared and patience has become your normal attitude towards annoyance. In this manner you can develop various virtues of sympathy, self-restraint, purity, humility, benevolence, nobility, generosity, etc.
Only a trained mind which utterly controls the body can inquire and meditate endlessly. So long as life remains, never for a moment lose sight of the object of your search and contemplation (Brahman), never for a moment allow it to be obscured by any terrestrial temptation.
During the inhalation the air comes out 16 digits. When the mind gets concentrated it will become less and less. It will come to 15, then 14, 13, 12, 10, 8 and so on. When you enter into very deep, silent meditation, breath will not come out of the nostrils.
There may be occasional slow movement of the lungs and the abdomen. From the nature of the breathing you can infer the degree of concentration of an aspirant. Watch the breath very carefully.
When you advance in the spiritual practice it will be very difficult for you to do meditation and office-work at the same time because the mind will undergo double strain. It works in different grooves and channels with different Samskaras during meditation. It finds it very difficult to adjust to different kinds of uncongenial activities. As soon as it comes down from the meditation it gropes in darkness. It gets bewildered and puzzled. It has to work in different grooves and channels. When you again sit for meditation in the evening you will have to struggle hard to wipe out the newly acquired Samskaras you have gathered during the course of the day and get a calm one-pointedness of mind. This struggle brings in sometimes headache. The Prana (energy) which moves inward in different grooves and channels and which is subtle during the meditation has to move in new, different channels during worldly activities. It becomes very gross during work.
When the mind becomes steady in meditation the eye-balls become steady. A Yogi whose mind is calm will have a steady eye. There will be no winking at all. The eyes will be lustrous, red or pure white.
The purifying process leads to a deeper insight into Truth. This is the action of Grace of the Lord upon the soul in meditation. In this inflowing Grace there forthwith arises that light of the mind into which God is sending a ray of His unclouded Splendour. This Light is vastly potent.
When the Sushumna Nadi is working, i.e., when the breath flows through both the nostrils, meditation goes on with ease and joy. The mind then is calm. There is an increase of Sattvaguna when Sushumna is operating. Sit for meditation the moment the Sushumna begins to flow.
Considerable changes take place in the mind, brain and the nervous system by the practice of meditation. New nerve-currents, new vibrations, new avenues, new grooves, new cells and new channels are formed. The whole mind and the nervous system are remodelled. You will develop a new heart, a new mind, new sensations, new feelings, new modes of thinking and a new view of the universe (as God in manifestation).
The meditation-room should be regarded as a temple of God. Talks of profane nature should never be indulged in the room. No vicious thoughts of rancorous jealousy, avarice are to be entertained there. Admittance should ever be sought in it with a pious and reverent mind. For, what we do, what we think and we speak of, leave their impressions in the room and if no care is taken to avoid them, they will exert their influence on the aspirant's mind and rendering his mind perverse and restive, make him incapable of attending to the devotion. The words uttered, the thoughts cherished, the deeds done are not lost, they are always reflected on the subtle layers of ether encircling the room where they are done and affect the mind invariably. As much as possible, efforts should be made to overcome them. This is to be done for a few months only. When the habit is changed, everything will be all right.
When the mind is Sattvic, you can get glimpses or flashes of intuition. You will compose poems. You will understand the significance of the Upanishads beautifully. But this stage will not last long in neophytes. Tamas and Rajas will try to enter the mental factory. In the beginning the stage of progress may be like the frog's, never steady and continuous. You may think that you have almost reached the goal, and experience for the next 15 or 20 days nothing but disappointment. It will be a jump from position to position, but not a continuous development. Have sustained, intense Vairagya and do intense protracted Sadhana. Be under the direct guidance and in close contact with your Guru for some years. You will have steady and continuous progress.
When you experience bliss in meditation, some peculiar sensation will disturb you and with this disturbance the sublime bliss will disappear. During meditation Sattva increases, but Rajas is ever trying to overcome Sattva. You feel the peculiar sensation of disturbance on account of entry of Rajas. The thought of any work that you will have to do may also cause disturbing sensation. Forget all works and speak to the mind. "I have nothing more to do. I have done everything." When Sattva increases through inquiry, vigorous Sadhana and greater Vairagya, this disturbance will vanish and you will experience deep meditation. The bliss also will last for a long time.
Siddhas, Devas and others surrounded Uddalaka Muni. Celestial-ladies flocked to him in great numbers. Devendra offered to the Muni his Devaloka. Uddalaka totally declined to accept anything. The ladies tried to entice him by their vile charms. They told him, "Take your seat in the celestial car. It will take thee to Devaloka. Here are the springs that confer Immortality. Here are the celestial nymphs to serve thee. Thy rare Tapas has brought all these for thee. Here is Chintamani." Uddalaka, the brave, resisted all temptations and shone in effulgence. He did not long for sensual objects. After six months the Muni awoke from his Samadhi. He would spend in one sitting, days and months and even years in deep Samadhi, and then would wake up. Bali was statue-like in Samadhi for a long period. Janaka remained statue-like in Samadhi for a long time. Prahlada seated himself statue-like in Nirvikalpa Samadhi for many years.