To have good foundation is to practice the Ngondro

So, it is very important to build a good foundation for the practice of this Great Secret, the Great Perfection, Great Wisdom. And to have this good foundation one is to practice the Ngondro and to accomplish the 500,000 Preliminary practices like 100,000 prostrations, 100,000 mandala offering, 100.000 recitations of 100 syllables, and bodhicitta and refuge prayers. It may sound very scary (laughed) but it is not that scary if you’re really into it. I don’t think it’s that hard. Those people who have read the biography of Patrul Rinpoche and other great masters in this lineage see how many practices they did in their lives. Patrul Rinpoche had completed 25 times of these 500.000 practices. It’s now still going on a lot. We have really diligent people in our monastery in Golog and some of them have completed nearly 30 times of these 500,000 Preliminary practices; and there are many of them, actually. Not only Longchen Nyingthig but all great lineages of Kagyupa, Sakyapa, Nyingmapa are based on this preliminary practice for the highly pure realization. The main reason is to purify oneself. Like doing prostration has the power to purify your physical stain, physical negativities. So do the recitation of 100 syllables. It has natural power to purify your internal negativities. So, I really think it is very important to understand the meaning or the use of these preliminary practices.

Cited in “The Longchen Nyingthig Lineage is About The Greatest Peace”, Hungkar Dorje Rinpoche

Dagpa Yeshe cites.