וַיִּקַּ֨ח מֹשֶׁ֜ה וְאֶלְעָזָ֤ר הַכֹּהֵן֙ אֶת־הַזָּהָ֔ב מֵאֵ֛ת שָׂרֵ֥י הָאֲלָפִ֖ים וְהַמֵּא֑וֹת וַיָּבִ֤אוּ אֹתוֹ֙ אֶל־אֹ֣הֶל מוֹעֵ֔ד זִכָּר֥וֹן לִבְנֵֽי־יִשְׂרָאֵ֖ל לִפְנֵ֥י יְהוָֽה׃ (פ)
And Moses and Eleazar the priest took the gold of the captains of thousands and of hundreds, and brought it into the tent of meeting, for a memorial for the children of Israel before the LORD.
Read Jewish philosophy on Numbers 31:54: Rambam's Guide for the Perplexed, Saadia Gaon, and classical Jewish philosophical sources, free online.