Goeika (a Buddhist hymn): "Ikenomizu Hitonokokoroni Nitarikeri Nigorizumukoto Sadamenakereba" (The water in river resembles a person's mind in that it becomes muddy at times and clear at other times without any patterns)
御詠歌「池の水ひとの心に似たりけり濁り澄むこと定めなければ」