大乘起信論裂網疏 3.49

3.49

由第七識恒與法癡相應，不如實知真法一故，令自與第八無始恒轉，令前六識依之得轉。心實無動，由不覺故謂之為動，動即是現行轉。現行之體即自證分，名為業相。是則一切心王、心所業相皆依第七無明而起，名為依他起性，故直名此第七為業識也。若觀動心即不生滅，即得入真如門。

Because the seventh consciousness is constantly associated with delusion regarding dharmas, and does not truly know the oneness of the true dharma, it causes itself and the eighth to operate constantly from beginningless time, and causes the prior six consciousnesses to be able to operate based upon it. The mind in reality has no movement; due to non-enlightenment it is called 'movement'. Movement is simply the operation of actual manifestation. The essence of actual manifestation is simply the self-corroborating part, which is named the 'karmic mark'. This being so, the karmic marks of all primary minds and mental factors arise based on the ignorance of the seventh, and are named the 'other-dependent nature'; therefore this seventh is directly named the 'karmic consciousness'. If one contemplates that the moving mind is itself neither arising nor ceasing, one then attains entry into the aspect of tathatā.