無量壽經連義述文贊 2.49

2.49

經曰「無量億劫」至「時時乃出」者，述云：此第三、辨佛難值也。帛謙皆云「如世間有優曇樹，但有實無有華也，天下有佛乃有華出耳。」今言靈瑞華者，即存震旦之名。時時者，即希出之義，以善時出故。

The sūtra says: from “In immeasurable kotis of kalpas” to “only appearing from time to time.” The commentary states: This is the third part, distinguishing that the Buddha is difficult to encounter. Both Bai [Yan's] and [Zhi] Qian's [translations] say: “Just as in the world there is the udumbara tree, which has fruit but no flowers, and only when a Buddha appears in the world do flowers emerge.” The present mention of the “wondrous auspicious flower” preserves the name used in China. “From time to time” signifies rare appearance, because it appears at an auspicious time.