וַיַּשְׁכֵּ֨ם דָּוִ֜ד בַּבֹּ֗קֶר וַיִּטֹּ֤שׁ אֶת־הַצֹּאן֙ עַל־שֹׁמֵ֔ר וַיִּשָּׂ֣א וַיֵּ֔לֶךְ כַּאֲשֶׁ֥ר צִוָּ֖הוּ יִשָׁ֑י וַיָּבֹא֙ הַמַּעְגָּ֔לָה וְהַחַ֗יִל הַיֹּצֵא֙ אֶל־הַמַּ֣עֲרָכָ֔ה וְהֵרֵ֖עוּ בַּמִּלְחָמָֽה׃
And David rose up early in the morning, and left the sheep with a keeper, and took, and went, as Jesse had commanded him; and he came to the barricade, as the host which was going forth to the fight shouted for the battle.
Read halakhic rulings (Jewish law) on I Samuel 17:20 from the Mishneh Torah and classical halakhic sources, free online.