The way is to recognize clearly the cause of one's suffering in countless lifetimes is selfishness. That includes suffering of death in this life as well as innumerable such suffering over previous lifetimes. In the context of relative truth, selfishness is a mistaken concept; in the ultimate truth, there is neither self nor life or death. Therefore, we must resolutely put an end to all those notions born of selfishness, such as "I want", "I hate", "I like", "I ..." and so forth.
~Depicted from THE HANDBOOK'S FOR LIFE JOURNEY - On Death And Rebirth-Key Points for Practicing Bodhicitta on Deathbed
Relatively speaking, the generation stage is already a great practice, but it is still an indirect path. We know that one cannot enter directly into the enlightened realm of the buddha by way of the generation stage alone; instead, one must first practice visualization with thangkas which, however, are painted by people and hence not quite the ultimate way. Whereas Dzogchen, by skipping these diversions and keeping only the essential point, enables the practitioners to attain the enlightened pure state directly and much faster through the practice of tögal. This is a very important point to note. However, tantric practitioners who do not have the capacity to practice Dzogchen must take the indirect path before reaching the final goal.
~Depicted from GATEWAY TO VAJRAYANA PATH - Sutra and Tantra: Similarities and Differences--based on the view of Rongzom Pandita
There is an analogy for this. When ink is poured on the snow, the snow will be turned into ink color. After it melts, the color can still be seen on the ground. Similarly, if karma is born of defilements, the karmic mark will be left in the alaya consciousness after defilements are gone. Karma (or cause) is kind of a unique ability. Although our eyes cannot see how rice seeds germinate, they do have within themselves the capacity to do so. Likewise, when a karmic seed is planted in the alaya consciousness, it will yield fruit when all the right conditions come together. This fruit is also called karmic effect. And this particular capacity of the alaya consciousness to yield karmic fruit is the inherent nature of cause.
~Depicted from THE RIGHT VIEW - On Cause and Effect
In sutra, ground is the illusory world we see in front of us, which includes sentient beings, the external world of mountains, rivers, earth, etc., and emptiness; fruition is the attainment of the three resultant bodies of buddhahood—the dharmakaya, sambhogakaya, and nirmanakaya. We ordinary people are not yet buddha, but through practice we can attain buddhahood after three asamkhyeya kalpas. Sentient being is the cause; buddhahood is the result.