“Its wall is one hundred forty-four cubits, by the measure of a man, that is, of an angel.” Revelation 21:17 This strange and Biblically unique grammatical construction seems very much in keeping with John seeing the 144 triangle, knowing it wasn't exactly a “measure”, yet made by man, and he puts an angel (which means “messenger”) in the verse to explain that it is a message, not a measurement per se. Otherwise, why not just say “The wall is 144 cubits.”?

The overcomers are referred to in Revelation 3:12:

“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.”