What does Revelation 3:15 mean?

He who overcomes, I will make him a pillar in the temple of my God, and he will go out from there no more. 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 out of heaven from my God, and my own new name.

He who has an ear, let him hear what the Spirit says to the assemblies.

“To the angel of the assembly in Laodicea write: “The Amen, the Faithful and True Witness, the Beginning of God’s creation, says these things:

So, because you are lukewarm, and neither hot nor cold, I will vomit you out of my mouth.

Because you say, ‘I am rich, and have gotten riches, and have need of nothing;’ and don’t know that you are the wretched one, miserable, poor, blind, and naked;

I counsel you to buy from me gold refined by fire, that you may become rich; and white garments, that you may clothe yourself, and that the shame of your nakedness may not be revealed; and eye salve to anoint your eyes, that you may see.