While it is certainly possible (and even probable) that lots of different kinds of cultural expressions will be present in the worship of heaven, there is no Scriptural proof of this, and there is certainly no proof that all cultural expressions will be there. For one thing, it is at least instructive to note that at least one aspect of cultural diversity is eliminated in this heavenly picture—their clothing (Rev 7:9). All of these people from various tribes, peoples, and nations are wearing the same thing: white robes. Where is the cultural diversity in that?
A passage often cited by evangelicals to prove that every cultural expression is legitimate since people from every nation will be admitted into heaven is Revelation 5:9:
And they sang a new song, saying, ‘Worthy are you to take the scroll and to open its seals, for you were slain, and by your blood you ransomed people for God from every tribe [phylēs] and language [glōssēs] and people [laou] and nation [ethnous].1
Here John uses four terms related to ethnic identity, but it is important to recognize that John uses the terms not to emphasize cultural distinctions between various people groups but rather to signify all peoples without national or cultural distinctions. For example, Mounce states of the terms in this verse, “It is fruitless to attempt a distinction between these terms as ethnic, linguistic, political, etc. The Seer is stressing the universal nature of the church and for this purpose piles up phrases for their rhetorical value.2 Likewise, Thomas argues, “The enumeration includes representatives of every nationality, without distinction of race, geographical location, or political persuasion.3
In other words, terms like ethnos, (“nation”), phylē (“tribe”), glōssa (“language”), and laos (“people”) do not refer to the culture (behavior) of people, but rather to the people themselves, and ethnic distinctions among people in heaven will be absent.
MacLeod summarizes common definitions for such ethnicity-related terms:
(1) The word “tribe” (phylē) denotes “a group bound together by common descent or blood-relationship.” In the New Testament most references are to the tribes of Israel. In Revelation 5:9 the word includes the redeemed from the Gentile world, which also includes tribal groups (Christian Maurer, “φυλή,” in Theological Dictionary of the New Testament, vol. 9 , 245–50, esp. 245, 250).