And he measured the wall thereof - In respect to its “height.” Of course, its length corresponded with the extent of the city.
An hundred and forty and four cubits - This would be, reckoning the cubit at eighteen inches, two hundred and sixteen feet. This is less than the height of the walls of Babylon, which Herodotus says were three hundred and fifty feet high. See the introduction to chapter 13 of Isaiah. As the walls of a city are designed to protect it from external foes, the height mentioned here gives all proper ideas of security; and we are to conceive of the city itself as towering immensely above the walls. Its glory, therefore, would not be obscured by the wall that was thrown around it for defense.
According to the measure of a man - The measure usually employed by men. This seems to be added in order to prevent any mistake as to the size of the city. It is an “angel” who makes the measurement, and without this explanation it might perhaps be supposed that he used some measure not in common use among people, so that, after all, it would be impossible to form any definite idea of the size of the city.
That is, of the angel - That is, “which is the measure employed by the angel.” It was, indeed, an angel who measured the city, but the measure which he employed was that in common use among people.