The starting-point of the career of Ashur is the city of Ashur, situated on the west bank of the Tigris, not far from the point where the lower Zab flows into the Tigris.  Ashur is therefore distinctly a local deity,... Ashur became the god of Assyria as the rulers of the city of Ashur grew in power,—in the same way that Marduk, upon the union of the Babylonian states under the supremacy of the city of Babylon, became the god of all Babylonia... Ashur was not symbolized exclusively by a statue, as Marduk and the other great gods were.  His chief symbol was a standard that could be carried from place to place, and indeed was so made that it could be carried into the thick of the fray, in order to assure the army of the god's presence.  The standard consisted of a pole surrounded by a disc enclosed within to wings, while above the disc stood the figure of a warrior in the act of shooting an arrow... It may be that the representation of the god by a standard was a consequence of the fondness that the rulers of Ashur manifested for perpetual warfare; or, in other words, that the god Ashur was represented by a standard so that he might be carried into the battle, and be moved from place to place.  At all events, the two things—the standard and the warlike character of the subjects of Ashur—stood in close relationship to one another, and the further conclusion is justified that when a military standard came to be chosen as the symbol of Ashur, the god was recognized distinctly as a god of war...
    ... The ideographs which the Assyrian scribes employed in writing the name of the god reveal the meaning they attached to it.  He is described ideographically as the "good god."  This interpretation accords admirably with the general force of the verbal stem underlying the name.  In both Hebrew and Assyrian a-sh-r signifies "to be gracious, to grant blessing, to cause to prosper."  Ashur, therefore, is the god that blesses his subjects, and to the latter he would accordingly appear as the "good god" par excellence... (The Religion of Babylonia and Assyria, Jastrow, 1898)