Why is the name of God's city inscribed on this pillar?
Revelation 3:12 (ESV)
12The one who conquers, I will make him a pillar in the temple of my God. Never shall he go out of it, and I will write on him the name of my God,and the name of the city of my God, the new Jerusalem, which comes down from my God out of heaven, and my own new name.
Having the city’s name inscribed on the saint indicates that the Lord considers him a bona fide citizen of this heavenly city, the New Jerusalem (see Galatians 4:26; Philippians 3:20).
12 The one who conquers, I will make him a pillar in the temple of my God. Never shall he go out of it, and I will write on him the name of my God, and the name of the city of my God, the new Jerusalem, which comes down from my God out of heaven, and my own new name.