Hazrat Inayat Khan on Samadhi:

The ordinary person knows that after deep sleep he is calm, reposed, his feeling is better, his thoughts clearer. The condition of Hal, or Samadhi, the highest condition, is the same as that of deep sleep, the difference being only that it is experienced at will. The difference between the perfect person and the ordinary person is only this, that the perfect person experiences consciously what the imperfect person experiences unconsciously. Nature provides all with the same experience, but most people are unconscious of the experience, which is to their disadvantage.

The fasting and abstinence, and all these things, were taught in order to develop the will-power, which results in self-discipline and which is the secret of all mastery; and it is by this power that the kingdom within is attained. Once man has touched his self within, the illusion becomes dissolved. The fear of death is caused by the consciousness of mortality. As long as one is unaware of one's immortal self one has the fear of death. Once the immortality of the soul is realized and the realization is no longer in one's imagination but has become a conviction, then one rises above the fear of death. This knowledge is gained fully when an adept is able to detach his soul from his body. It is this state which is called by Yogis Samadhi and by Sufis Najat.