In chapter 7:9 we have a picture of a great multitude of people dressed in white and standing around the Throne of God. Heb. 12:22 tells us that Mt. Zion is another symbolic representation of the church. Micah 4:7 says that Christ is reigning on Mt. Zion; therefore, Christians are gathered around Mt. Zion today and are dressed in white robes. They have palms in their hands, which shows that we serve him continually.
This parallel can once again be used to determine what parallels of the Old Testament that we are dealing with in Revelation.
This drawing shows exactly what we are being told in Rev. 7:14-15.