I Chronicles 16:37 Halakhah

וַיַּֽעֲזָב־שָׁ֗ם לִפְנֵי֙ אֲר֣וֹן בְּרִית־יְהוָ֔ה לְאָסָ֖ף וּלְאֶחָ֑יו לְשָׁרֵ֞ת לִפְנֵ֧י הָאָר֛וֹן תָּמִ֖יד לִדְבַר־י֥וֹם בְּיוֹמֽוֹ׃

So he left there, before the ark of the covenant of the LORD, Asaph and his brethren, to minister before the ark continually, as every day’s work required;