大毘盧遮那成佛經疏 10.86

10.86

次嚕捺囉，亦佛所化身，是摩醯首羅之化身也（亦名伊舍那）嚕馱囉（二合）也（即以本名為真言也）以嚕字為心。馱囉是授與之義，猶自多有能惠他人。所謂諸乘，乘即已也字義也。自通達如是寶乘，能遍施一切眾生。嚕即無塵垢三昧，自得此三昧復以施人也。

Next is Rudra, who is also an emanation body of the Buddha, an emanation body of Maheśvara (also named Īśāna). *Rudrāya* (namely, using his original name as the mantra) takes the syllable *ru* as its heart. *Drā* has the meaning of bestowing, like having much oneself and being able to grant it to others. The so-called vehicles (yāna): vehicle is the meaning of the syllable *ya*. Having penetrated such a jewel vehicle oneself, one can universally bestow it upon all sentient beings. *Ru* is the stainless samādhi; having attained this samādhi oneself, one further bestows it upon others.