大毘盧遮那成佛經疏 13.19

13.19

達麼馱都是法界也，法界者即是佛身。下句云我者，言我即是法界也。又此行者雖未能即體真性，但作此印而誦真言，亦即體同法界也。其印以二空指內掌中，以左右手地水火三指壓而作拳，竪二風令直（兩手各別作拳而竪風指也），先竪二指合當胸，即向裏而轉，令兩手指從頂兩邊各近左右頰頸、而向裏曳稍下曳之。謂初竪指，稍令指頭向下、指背向裏，近頭頰漸漸指頭近下也，至心即散手也。凡誦真言作印，喻如耕牛二牛同進，不得前後也。

*Dharmadhātu* is the realm of phenomena; the realm of phenomena is the body of the Buddha. The lower phrase says "I," meaning "I am precisely the dharmadhātu." Moreover, although this practitioner has not yet realized the true nature in substance, merely by forming this mudrā and reciting the mantra, his substance also becomes identical to the dharmadhātu. As for its mudrā: bend the two space fingers inside the palms, press them with the earth, water, and fire fingers of both left and right hands to form fists, and erect the two wind [fingers] straight (each hand separately forms a fist and erects the wind finger). First erect the two fingers together in front of the chest, then rotate them inward, causing the two fingers from both sides of the crown to approach the left and right cheeks and neck respectively, and draw them inward, pulling them slightly downward. That is to say, when first erecting the fingers, make the fingertips point slightly downward with the backs of the fingers inward; bringing them close to the head and cheeks, gradually lower the fingertips, and upon reaching the heart, release the hands. Whenever reciting mantras and forming mudrās, it is like two plowing oxen advancing together: neither may be ahead or behind.