וַיִּשְׁלַח֩ דָּוִ֨ד אֶת־יָד֜וֹ אֶל־הַכֶּ֗לִי וַיִּקַּ֨ח מִשָּׁ֥ם אֶ֙בֶן֙ וַיְקַלַּ֔ע וַיַּ֥ךְ אֶת־הַפְּלִשְׁתִּ֖י אֶל־מִצְח֑וֹ וַתִּטְבַּ֤ע הָאֶ֙בֶן֙ בְּמִצְח֔וֹ וַיִּפֹּ֥ל עַל־פָּנָ֖יו אָֽרְצָה׃
And David put his hand in his bag, and took thence a stone, and slung it, and smote the Philistine in his forehead; and the stone sank into his forehead, and he fell upon his face to the earth.
Read halakhic rulings (Jewish law) on I Samuel 17:49: and classical halakhic sources.