The record in Revelation 7:9-17 parallels in several ways the description of New Jerusalem in Revelation 21–22. Part of note 2 on Revelation 7:9 in the Recovery Version New Testament says, “The record in vv. 9-17 describes in a general way the scene from the time of the rapture of the believers to their enjoyment in eternity.”
One striking parallel is “These are those who…have washed their robes and made them white in the blood of the Lamb” (Rev. 7:14) and “Blessed are those who wash their robes that they may have right to the tree of life and may enter by the gates into the city” (22:14).
The result of washing in 22:14 indicates that the multitude in Revelation 7 will be constituents of New Jerusalem.
Another strong similarity is “They are before the throne of God and serve Him day and night…” (7:15) and “The throne of God and of the Lamb will be in it, and His slaves will serve Him” (22:3). Prior to the Lord’s second coming, the throne of God is in heaven, to which this multitude has been raptured (see link to note in first paragraph). In eternity the throne is in New Jerusalem, which has come down “out of heaven” to the new earth (Rev. 21:2, 10).
“They will not hunger any more, neither will they thirst any more” (7:16a) is fulfilled in New Jerusalem by the fruit of the tree of life and the river of water of life (22:1-2).
“The Lamb who is in the midst of the throne will shepherd them…” (7:17) matches “the throne of God and of the Lamb (22:1). The shepherding in 7:17 includes the tree and river in 22:1-2 and the Lord God’s shining on us in 22:5. These parallels show that the eternal blessing in New Jerusalem are presented in a general way in Revelation 7.