When he had consulted with the people, he appointed men to sing to Yahweh and give praise in holy attire as they went out in front of the army, and say,
“Give thanks to Yahweh;
for his covenant faithfulness endures forever.” Bible see other translations

“in holy attire.” See commentary on Psalms 29:2. However, scholars are divided on how to translate 2 Chronicles 20:21. It is possible to understand the Hebrew text to be saying more like the ESV is translated: “praise him for the splendor of his holiness.”

Commentary for: 2 Chronicles 20:21