וַיִּתֵּ֞ן לִפְנֵ֨י אֲר֧וֹן יְהוָ֛ה מִן־הַלְוִיִּ֖ם מְשָׁרְתִ֑ים וּלְהַזְכִּיר֙ וּלְהוֹד֣וֹת וּלְהַלֵּ֔ל לַיהוָ֖ה אֱלֹהֵ֥י יִשְׂרָאֵֽל׃ (פ)
And he appointed certain of the Levites to minister before the ark of the LORD, and to celebrate and to thank and praise the LORD, the God of Israel:
Read kabbalistic (mystical) interpretation of I Chronicles 16:4: and classical mystical sources.