‘He who overcomes, I will make him a pillar in the Temple of my God, and he will leave it no more, 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 Heaven from my God, and my own new name.'
Here is Christ's clear indication that the coming Temple of God is a spiritual one. Those who are overcomers will be made part of that Temple, the guarantee that they will be in the presence of God forever (see John 17:12; John 18:9).
They will also be clearly identified as His. He will write on them the name of God, to show they are His, and the name of the new Jerusalem which descends from Heaven (Revelation 21:2; Revelation 21:10) to show that they belong there, and Christ's own new name to show that they belong to the glorified Christ.
This new name, only known to those who receive it (Revelation 2:17), is the sure sign that they are His. In Revelation 2 they wear it proudly on the pure white stone, probably seen as on their breasts and on their shoulders as with the High Priest. Here the name is written personally on them (see Revelation 14:1; Revelation 22:4. Compare Isaiah 49:16 where the names of His own are written on His hands). We must not overpress the symbolism. It is the idea that matters, not the form in which it is put. So once again, in a different form, the overcomer is guaranteed eternal life.
This designation with a new name is spoken of in Isaiah 65:15. There the so-called people of God have forsaken the Lord, and have prepared a table for Fortune and filled up cups with mingled wine to Destiny, and because of this they themselves are rejected and forsaken and their name will become a curse. They have become enslaved by the occult, and caught up in fortune telling and belief in Fate. So God promises that He will call by another name those who have sought Him and are faithful to Him, His chosen ones, His servants (Isaiah 65:9-10). How much clearer could He have put it that those who take the new name have replaced those who bore the old, for they are the true seed of Jacob (Isaiah 65:9).