Ngondro

Ngöndro (Tib. སྔོན་འགྲོ་, Wyl. sngon ‘gro) — the preliminary or ‘foundation’ practices of Vajrayana Buddhism. The ngöndro practices are profound and powerful means for effecting a deep purification and transformation, at every level of our being. Not only do they prepare the practitioner for the profound path of Vajrayana and teachings of Dzogchen, but they also lead him or her gradually towards the experience of enlightenment.

Dilgo Khyentse Rinpoche said:

When we take our first steps on the Path, we are not yet capable of helping others. To accomplish the good of others, we must first perfect ourselves, by purifying and transforming our minds. This is the aim of what we call the preliminary practices, which establish the foundations of all spiritual progress. You may feel like dispensing with these foundations in order to practice teachings that you think are more profound, but if you do so, you are building a palace on the surface of a frozen lake.

(rigpawiki)