Reference for I Chronicles 9:32

וּמִן־בְּנֵ֧י הַקְּהָתִ֛י מִן־אֲחֵיהֶ֖ם עַל־לֶ֣חֶם הַֽמַּעֲרָ֑כֶת לְהָכִ֖ין שַׁבַּ֥ת שַׁבָּֽת׃ (ס)

And some of their brethren, of the sons of the Kohathites, were over the showbread, to prepare it every sabbath.