注大乘入楞伽經 8.164

8.164

言優曇花，三世之中無有見者，如來則世間悉見。何得說佛如優曇花？明為眾生如是譬喻，故說化佛難見易見，非說自真實法故。自法者，乃是如來所證境界，世無與等，不可為譬，非凡夫心識所見之相，是皆不能信受耳。

This means that among the three periods of time, no one has ever seen the uḍumbara flower, whereas the Tathāgata is seen by all in the world. How could the Buddha be said to be like the uḍumbara flower? It explains that such metaphors are used for sentient beings; hence it speaks of transformation Buddhas as difficult to see or easy to see, not of his own real Dharma. His own Dharma is the realm realized by the Tathāgata, to which nothing in the world is equal, which cannot be exemplified, and which is not a form seen by the mind and consciousness of ordinary persons; thus none of them can faithfully accept it.