大毘盧遮那成佛經疏 2.74

2.74

第四十五「泥心」，梵本缺文，不釋。阿闍梨言：「此是一向無明心也。乃至目前近事亦不能分別記憶，故律云猶如泥團。又如泥濘，以淖弱故，難事越度。要令有所由藉，謂假橋梁等方能越之。若覺有此方便，必須歸憑善友，令方便開發，乃能漸去無知，還生慧性也。」

The forty-fifth, the "mud mind," lacks text in the Sanskrit manuscript and is not explained [in the root text]. The ācārya said: "This is an exclusively ignorant mind. It cannot distinguish or remember even immediate matters before its eyes; hence the Vinaya says it is like a lump of mud. Moreover, it is like muddy ground: because it is soft and slippery, it is difficult to cross. One must rely on something—namely, using a bridge or the like—before one can cross it. If one realizes this expedient, one must take refuge in and rely on good spiritual friends to unfold expedients, whereby one can gradually dispel ignorance and regain one's nature of wisdom."