Nehemiah 10:37 Midrash

וְאֶת־בְּכֹר֤וֹת בָּנֵ֙ינוּ֙ וּבְהֶמְתֵּ֔ינוּ כַּכָּת֖וּב בַּתּוֹרָ֑ה וְאֶת־בְּכוֹרֵ֨י בְקָרֵ֜ינוּ וְצֹאנֵ֗ינוּ לְהָבִיא֙ לְבֵ֣ית אֱלֹהֵ֔ינוּ לַכֹּ֣הֲנִ֔ים הַמְשָׁרְתִ֖ים בְּבֵ֥ית אֱלֹהֵֽינוּ׃

also the first-born of our sons, and of our cattle, as it is written in the Law, and the firstlings of our herds and of our flocks, to bring to the house of our God, unto the priests that minister in the house of our God;