Revelation 21:17

And he measured the wall thereof, a hundred and forty and four cubits, according to the measure of a man, that is, of an angel.

One hundred and forty and four cubits ... The problem here is that a wall 266 feet high seems totally out of proportion for a city more than 30,000 times that high! Beckwith applied the dimension only to the thickness of the wall. "The height of it is included in the height of the city in Revelation 21:16."[42] This, however, helps very little, because a wall of such thickness could not sustain itself at a height of 30,000 times its thickness, except in the event of the wall being a shield affixed to and part of the city itself. Perhaps that is the way we should view it, the fact of its being made of jasper (the diamond, which is the hardest of all material substances) adding some logic to such an interpretation.

According to the measure of a man ... This just means that John was not referring here to any trick measurements.