oneness with it. The Soul (Atman) experiences its oneness with the Cosmic Soul
An ancient Hindu song goes likes this:
In Savikalpa Samadhi yoga
You will drown yourself (ego) in yourself (Soul)
In Nirbikalpa Samadhi yoga
You will find yourself (Soul) in yourself (Spirit).
Obstacles to samadhi
"Vyaadhi-styaana-samshaya-pramaada-aalasya-avirati-bhraantidarshana alabdhabhumikatvaanavasthitatvaani-chitta-vikshep-teantaraayaah" (PYS Ch 1, Su-30)
Disease, languor, doubt, carelessness, laziness, worldly-mindedness, wrong or delusive perceptions, non-achievement of a state, instability are the nine causes of distractions of the mind creating great obstacles in the practice of Samadhi.
Disease in the body is obviously a hindrance, because it draws the mind again and again back to the body and it is difficult to keep it directed inwards. Perfect good health is needed to proceed successfully in the practice of Samadhi.
Some people have an apparently healthy physical body, but lack nerve power so that they always feel a lack of energy in their body. This chronic fatigue is in many cases psychological in origin and due to the absence of any definite and dynamic purpose in life. In other cases it is due to some defect in the Pranamaya kosha which results in an inadequate supply of prana energy to the physical body.
An unshakable faith in the efficacy of ' yoga is a must for its successful practice. In the Divine adventure that the Yogi has undertaken, the objective is unknown and there are no clear standards by which he can judge or measure his progress. Doubts of various kinds therefore, arise. Is here really any Ultimate Reality to be realized? Are the methods he is using effective. Are the methods right for him? Does he have the capacity to proceed ahead. These and many other doubts come up in the mind form time to time specially when he is passing through the periods of depression, which comes inevitably in the path of every aspirant. It is at this time he needs ‘Shraddha' unshakable faith in his objective, in himself, and the methods he has adopted. If he can ignore the depressive tendencies, even though he feels them he will surely succeed. If he allows these doubts and moods to interfere in his sadhana and relaxes his efforts he may get side tracked or abandon the practice all together.
This is a weakness which prevents a man from achieving eminence in any line of endeavor