金光明經文句記 3.205

3.205

二、「往耆」下，釋出往。王城靈鷲雖俱是地，山為佛居，故表果地；信相在城，合表因地。今以出往，表因趣果。

Second, from "Went to Gṛdhrakūṭa..." onward, explaining the setting forth. Although both the royal city and Vulture Peak are earthly places, the mountain was the dwelling of the Buddha, and therefore signifies the ground of fruition; Ruciraketu was in the city, which accordingly signifies the ground of cause. Now, by setting forth, it signifies the cause heading toward the fruition.