וַיֶּחֱזַ֨ק דָּוִ֤ד מִן־הַפְּלִשְׁתִּי֙ בַּקֶּ֣לַע וּבָאֶ֔בֶן וַיַּ֥ךְ אֶת־הַפְּלִשְׁתִּ֖י וַיְמִיתֵ֑הוּ וְחֶ֖רֶב אֵ֥ין בְּיַד־דָּוִֽד׃
So David prevailed over the Philistine with a sling and with a stone, and smote the Philistine, and slew him; but there was no sword in the hand of David.
Read midrashic interpretation of I Samuel 17:50: and classical rabbinic exegesis.