וַיִּקַּ֨ח הָעָ֧ם מֵהַשָּׁלָ֛ל צֹ֥אן וּבָקָ֖ר רֵאשִׁ֣ית הַחֵ֑רֶם לִזְבֹּ֛חַ לַֽיהוָ֥ה אֱלֹהֶ֖יךָ בַּגִּלְגָּֽל׃
But the people took of the spoil, sheep and oxen, the chief of the devoted things, to sacrifice unto the LORD thy God in Gilgal.’
Read halakhic rulings (Jewish law) on I Samuel 15:21: and classical halakhic sources.