אָ֭דָם לַהֶ֣בֶל דָּמָ֑ה יָ֝מָ֗יו כְּצֵ֣ל עוֹבֵֽר׃
사람은 헛것 같고 그의 날은 지나가는 그림자 같으니이다
Rashi on Psalms
his days are as a fleeting shadow Solomon said (Ecc. 6:12): “that he do them like a shadow,” but he did not explain whether [this refers to] the shadow of a palm or the shadow of a wall, which are permanent. His father already explained, “as a fleeting shadow,” the shadow of a flying bird.