華嚴經探玄記 19.57

19.57

第二不壞迴向知識中，初舉法勸修內，城名樓閣者，大悲依智勝出之狀。海師自在者，於佛法海及生死海能善通達及運度，故以為名。教問可知。

Regarding the spiritual friend of the second, the Indestructible Dedication: first, in presenting the Dharma and encouraging practice, the city named "Upper Story" depicts the superior emergence of great compassion relying on wisdom. The "Master of the Sea, Free and Sovereign" is named because he can skillfully penetrate and ferry [beings] across the sea of the Buddha-Dharma and the sea of saṃsāra. The instruction to inquire can be understood.