妙法蓮華經玄義 7.246

7.246

次、用蓮華譬四諦者，烏皮譬界內苦，白肉譬界內集，泥譬界外集，水譬界外苦，道滅可知。此通譬四種四諦也。

Next, using the lotus flower as a metaphor for the four noble truths: The black skin illustrates suffering within the realms; the white meat illustrates origination within the realms; the mud illustrates origination beyond the realms; the water illustrates suffering beyond the realms; path and cessation can be understood from this. This generally illustrates the four types of four noble truths.