וַיִּשְׁלַח֩ דָּוִ֨ד אֶת־יָד֜וֹ אֶל־הַכֶּ֗לִי וַיִּקַּ֨ח מִשָּׁ֥ם אֶ֙בֶן֙ וַיְקַלַּ֔ע וַיַּ֥ךְ אֶת־הַפְּלִשְׁתִּ֖י אֶל־מִצְח֑וֹ וַתִּטְבַּ֤ע הָאֶ֙בֶן֙ בְּמִצְח֔וֹ וַיִּפֹּ֥ל עַל־פָּנָ֖יו אָֽרְצָה׃
大衛伸手到袋中，從裡面取出一塊石子，用機弦甩出去，打中那非利士人的額頭；石子嵌進他的額內，他就仆倒在地，面朝下。
Rashi
And he fell face downward. He should have fallen backwards since he had been struck on his forehead.26The impact should have made him fall backwards. But, in order that Dovid should not be troubled to walk [the extra distance] and cut off his head, for Dovid now saved twelve amos and two zeres; for his height was six amos and a zeres, Dovid saved [walking] his entire height back and hs entire height forward.27Another reason why he fell face downward is because ה׳ had decreed that the mouth that blasphemed shall lick the dust of the earth.