大毘盧遮那成佛經疏 13.67

13.67

Next is the Seal of Binding the Great Boundary. Based on the method of the Tathāgata's hook seal above, simply raise the water finger of each of the two hands to stand straight up; that is it (inquire further into this, as it is not clear). The 'great boundary' here means from the initial generation of the great bodhicitta up to the attainment of buddhahood, having no interruption in the interim, neither returning to saṃsāra nor retrogressing from bodhi; this is the meaning of the great boundary. The homage of the mantra is as before.