Chandrakirti was the head abbot of Nalanda Monastic University. He was not only a great scholar, but was also one of the eighty-four mahasiddhas. The biographies of Chandrakirti tell how he could pass his arms through stone pillars, and that he could literally milk cows painted on thangkas. This great master had boundless realization of the true nature, yet he continuously emphasized the importance of good conduct to his students and practiced this himself.

Like Chandrakirti, Shantarakshita was once the head abbot of Nalanda Monastic University, and was also both a great scholar and siddha. Shantarakshita taught that we should continually balance absolute and relative truth in our practice. When Shantarakshita came to Tibet, he did not give Madhyamaka teachings right away. First, he gave instructions on taking refuge. Then he gave teachings on the ten virtuous activities, and after that he taught the five skandhas. He made certain that the Tibetan people were grounded in the relative truth before introducing them to the absolute truth.

… The practice of good conduct is always related to the laws of cause and effect, or karma. This means that as Dzogchen practitioners, we need to know what types of actions actions yield positive and negative results, adopting the positive and avoiding the negative. Yet just as our conduct must not be lost in the view, the view must not be lost in our conduct. In other words, even though we follow the systems of good behavior taught in the Dharma and practiced in the societies where we live, and even though we’re very careful regarding karma, we should not become regimented and petty. The view is as vast as space; the conduct is refined like barley flour. Be utterly open, and do what is good.”

Venerable Khenpo Rinpoches
The Beauty of Awakened Mind: Dzogchen Lineage of the Great Master Shigpo Dudtsi (pgs 183-184)

Photo of Ven. Khenpo Tsewang Dongyal Rinpoche praying at Padma Gochen Ling in Monterey, Tennessee around 2006, by Libba Gillum Miller.