Quoted in Sogyal Rinpoche, The Tibetan Book of Living and Dying (2008), p. 21.
Jigme Lingpa was a Tibetan tertön of the Nyingma sect of Tibetan Buddhism. He was the promulgator of the Longchen Nyingthik, the Heart Essence teachings of Longchenpa, from whom, according to tradition, he received a vision in which the teachings were revealed. The Longchen Nyingthik eventually became the most famous and widely practiced cycle of Dzogchen teachings. Wikipedia
Quoted in Sogyal Rinpoche, The Tibetan Book of Living and Dying (2008), p. 21.