The problem

The look-alikes become a problem because certain scriptural passages go beyond asserting YHWH’s greatness or power; they acclaim his uniqueness. If Isaiah had been satisfied to deny that any other god can match the strength of YHWH, the problem of the look-alikes would not have arisen; it would have been enough to say that those other so-called deities just could not match YHWH’s power. But Isaiah seems to deny that there is any god other than YHWH at all, and that denial is found in the collection of holy Scripture, with the result that many of the readers of Scripture have believed him. Once it has become clear, however, that Israel’s neighbors worshiped national gods who seem very like YHWH in numerous respects, such readers no longer know what to make of Isaiah’s proud boast.—Robert Goldenberg in Divine Doppelgängers: YHWH’s Ancient Look-Alikes, p. 88