Samadhi is the eighth limb of asthanga yoga.
तदेवार्थमॉर्निर्भसँ स्वरुप शून्यमिव समाधि
Transforming one’s own form into void is called Samadhi. Thus as one progresses through the stages of meditation, a stage is reached wherein the seeker has no awareness of his body or mind. Everything seems to be void. Then the seeker attains a divine power which is called as cosmic energy. This cosmic energy is achieved through two means 1) through Samadhi and 2) through bahya pranayama. Bahya means external. It done by inhaling as deeply as possible followed by exhaling as deeply as possible and holding the breath at this instant and imposing the three bandhas simultaneously. One can obtain cosmic energy through this process also. One who is dedicated in his attempts to get dissolved in the void and the one who is ready to perish in his path to salvation only will survive and eventually succeeds in achieving everything. On the contrary, one who is filled with ego and attitude will be lost forever. Thus in order fill one’s own self, he should become a lake and one who is on the peaks of egoism needs to undergo the cycle of practice of meditation once again because the greatest impediment in the path of Samadhi is ego.
One who achieves the state of Samadhi does not desire to achieve anything or to eat anything. Nature also abides by the instructions of such a person. Surrendering one’s own self to god will enable him to endowed with divine qualities and eternal bliss. In such a system the seeker enjoys a phenomenal bliss and peace. When this enjoyment is compared with the worldly pleasures, it is vividly evident that the bliss enjoyed through the path of meditation proves to be a million times better than any materialistic pleasure.
Eyes, nose, ears and other sense organs cease to function in the state of Samadhi. It also results in the fusion of physical and mental acts. In this state the seeker exists as a mere existence of power. Hi spiritual consciousness alone prevails in this state. The mind tends to become introverted in the state of Samadhi i.e., it tends to dwell in the supreme consciousness and thus it is affected by any worries of the materialistic world. This state is not a result of forgetfulness or lethargy or unconsciousness but it is a total conscious state. However this state cannot be described in words. But the words like brahmanand avastha (blissful state), turiyavastha etc can be used to indicate this state. This state is different from waking state, dreaming state or latent state. Thus it is called the turiy avastha which means the fourth state. The seeker experiences the blissful state which is hundred times happier than any the enjoyment given by any materialistic pleasure. Thus this state is commonly known as anandavstha and brahmananda avastha.