The Mystery of Samadhi

Even the best of meditation, in the initial stages, it's difficult to attain calmness of mind. One may attain deep samadhi and then one can stay in that for a long period of time. But beyond that, it still goes away. Another insight he says, nachayams, titas chalati, taktotah. Very interesting. He says, once attaining to this, one can never lose it again.