Why is the bride in Revelation depicted as wearing white linen?
The bride in Revelation is depicted in linen, bright and white and clean, because she pictures a chaste, pure virgin espoused to one husband, Christ. The white clothing symbolizes the virgin bride's purity, the church presented to Christ as pure.
Les explains that the writer is addressing Gentile believers, including Jews in the Age of Grace, members of the Body of Christ. He says he is jealous over them with a godly jealousy, for he has espoused them to one husband, that he may present them as a chaste or pure virgin to Christ. Les calls this a beautiful picture and says this is why the bride is depicted in Revelation as clothed in linen, bright and white and clean: it is the whole concept of a virgin bride, and she is depicted in white because of her purity. The context also mentions the ancient cultural habit where parents would pair the children, which stands behind the espousal imagery.
And to her was granted that she should be arrayed in fine linen, clean and white: for the fine linen is the righteousness of saints.