Among other things we find this line:
Your gates shall always be open; day and night they shall not be shut, so that nations shall bring you their wealth, with their kings led in procession. For the nation and kingdom that will not serve you shall perish; those nations shall be utterly laid waste (60.11-2).
This obviously the source of the parallel description of the heavenly Jerusalem described in Revelation 21, which is a metaphor for the church herself. Nota bene: the angel tells John that he will show him the bride, the wife of the Lamb (21.9), which is obviously a reference to the church, and then he is shown the great city. Thus John the Seer interprets the heavenly Jerusalem as the body of believers.
John likewise says of the city that Its gates will never be shut by day (21.25), and that The nations will walk by its light, and the kings of the earth will bring their glory into it. . . . People will bring into it the glory and the honor of the nations (vv. 24, 26). Of course if they are coming into the bride of Christ, this implies repentance and faith. And for John, too, they are coming into the bride of Christ, into the body of believers, from outside. Since the judgment has already taken place (20.11-5), where else are they going to be coming from except the lake of fire? What else is there outside the city? It is clear that the nations and kings in Revelation are the enemies of the bride who perpetually persecute her. They are punished by God and destroyed, but evidently they return from this and are reconciled to the bride and join themselves with her. It is also clear that the kings are joined to the bride post-judgment because its state of being is eschatological and sanctified: Nothing accursed will be found there anymore . . . And there will be no more night (22.3, 5).
John arguably interprets this destruction of the inimical kingdoms as their judgment and subsequent repentance. In a manner similar to Origen, Gregory of Nyssa, and others, we may understand the destruction of the nations and those in the lake of fire as a destruction of sin, rather than of the person. The person is saved though the sin and the sinful identity is destroyed.