וְהַמַּ֗יִם גָּֽבְר֛וּ מְאֹ֥ד מְאֹ֖ד עַל־הָאָ֑רֶץ וַיְכֻסּ֗וּ כָּל־הֶֽהָרִים֙ הַגְּבֹהִ֔ים אֲשֶׁר־תַּ֖חַת כָּל־הַשָּׁמָֽיִם׃
물이 땅에 더욱 창일하매 천하에 높은 산이 다 덮였더니
The Midrash of Philo
Why did the water overflow fifteen cubits above all the highest mountains? (Genesis 7:19). With respect to the literal statement we must remark that the excess was not merely one of fifteen cubits above all high mountains but above those which were a great deal more lofty and high than some others; therefore it was a great deal more than that height above the lower ones. But we must interpret this statement allegorically; for the loftier mountains shadow forth the senses in our body, because it has been permitted to them to occupy the abode of stability in the lofty region of our head. And there are five numbers of these, each to be considered separately, so that they amount in all to fifteen.