“in holy attire.” The Hebrew word translated “attire” is hadarah (#01927 הֲדָרָה), which the HALOT Hebrew and Aramaic Lexicon of the Old Testament defines as “holy adornment,” while the Holladay Hebrew and Aramaic lexicon has “attire.” The NET version has “holy attire,” and the NET text note reads, “That is, properly dressed for the occasion.” This is a reference to the public worship of God in attire that is befitting who He is. We are to worship God all the time, and this verse is certainly not saying that we should live day and night in clothes fit for public worship. However, when we engage in public worship, we should dress in a way that honors God.
The phrase translated “holy attire” appears five times in the Hebrew Old Testament, and four of those times are very similar (1 Chron. 16:29; 2 Chron. 20:21; Ps. 29:2 and Ps. 96:9). The use in 2 Chronicles 20:21 seems to clearly set the meaning, so much so that the ESV, which went with a translation influenced by the Ugaritic language here in Psalm 29:2, used “holy attire” in 2 Chronicles. But there does not seem to be any good reason that the meaning of the Hebrew phrase would change in the four verses that are so similar. There seems to be no good reason that “holy attire” would not be the meaning of the phrase in the four similar verses if it was the meaning in 2 Chronicles 20:21.
It also fits with the scope of Scripture that the Bible would speak of being appropriately dressed when worshiping God. Appropriate dress is certainly mentioned in other places in the Bible, such as Ezekiel 44:18 and 1 Timothy 2:9. We must be careful, however, not to read our modern way of life back into this verse and expect people to have a set of special clothing for public worship. In the Biblical times it was common that a person would only have one cloak (see commentary on Exod. 22:27). In that case, appropriate dress would be making sure that the garment you were wearing was presentable in public; for example, that it was not covered in mud or had animal blood on it from an animal that you had just killed and dressed out. In that light, it is noteworthy that the garments of the holy people coming with Christ to the Battle of Armageddon are white and “clean” (Rev. 19:14).
Due to evidence from the Ugaritic language, some modern versions read something like worship Yahweh “in the splendor of holiness” (ESV). But although that translation has the possibility of being correct (or could be a meaning that is an undertone), it does not seem to catch the meaning of the verse as well as “holy attire.” For one thing, Yahweh always has splendor and holiness, and also, Psalm 29:1-2 says to “ascribe” to Yahweh glory, the glory due his name. One way we could ascribe to Yahweh the glory due Him would be that when we enter holy places we show our respect to Him by dressing appropriately. A number of translations support the translation “holy attire” (cp. BBE; NASB; NET; Rotherham; Moffatt Bible).
It is also worth noting that our modern culture promotes a “love me like I am” attitude, no matter what the “I am” is. Thus, in many “seeker friendly” churches today, people come to church dressed in every sort of garb without any thought to the fact that we serve a holy God who we are supposed to please by our words and actions. While that may help people come to Christ, it should not be the norm for mature Christians. Yes, our worship benefits us, but the whole point is that we worship God because HE deserves it; so does He not also deserve that the way we appear before Him and appear in public worship is important? In the Old Testament, the person who approached God had to bring an offering; the fact that “they came at all,” a common modern sentiment, was not good enough. There is grace today, and people can come to public worship dressed any way they wish, but should they? The evidence of the text is “No.” There is a value to wearing “holy attire” even if that only means you thought about it and it is “clean.”