“When you accomplish calm abiding, not only does it counteract the fault of your wisdom consciousness wandering off while correctly investigating selflessness. The fault of distraction to other objects stops for all analytical meditations that you do with the wisdom of individual investigation: on impermanence, actions and their effects, the disadvantages of cyclic existence, love, compassion, training in the mind of enlightenment, and so forth. Then, since you get involved in each individual object, whatever it may be, without being distracted to something else, everything virtuous you do is very powerful. As long as you have not obtained calm abiding, due to predominant distraction to other objects any virtuous practice you do will be weak.”
From The Medium Treatise on the Stages of the Path to Enlightenment by Je Tsong Khapa
As translated in: Middle Length Lam-Rim with Trijang Rinpoche’s Additional Outlines by Lama Tsongkhapa (and Trijang Rinpoche). Translated by Philip Quarcoo. Unpublished DRAFT translation (May 2012) by FPMT, Inc. Download the PDF here.