“Ever-enhancing your enlightened motive of bodhicitta is the central axle of the Mahayana path. It is the basis and foundation for great waves of (enlightening) conduct. Like a gold-making elixir, (it turns) everything (you do) into the two collections, (building up) a treasure of merit gathered from infinitely collected virtues. Knowing this, bodhisattvas hold this supreme precious mind as their innermost practice. I, the yogi, have practiced just that. You who also seek liberation, please cultivate yourself in the same way.”
From The Concise Treatise on the Stages of the Path to Enlightenment by Je Tsong Khapa as published in Lines of Experience by Lama Je Tsong Khapa, translated by Sherpa Tulku, Khamlung Tulku, Alexander Berzin and Jonathan Landaw, which is included in Illuminating the Path to Enlightenment by His Holines the 14th Dalai Lama, translated by Geshe Thupten Jinpa. PDF available from Lama Yeshe Wisdom Archive.