A vengeful God?

How could an atheist or poorly educated {and most people today are!} non-believer possibly grasp that the 'God of the Old Testament' and 'The God of the New' are the same person if they have never studied the Scriptures in an unblinkered fashion?
Professor Dawkins is always most ready and willing to speak disparagingly of "the vengeful God of the OT."
I could point out to him that in Exodus 20, The Commandments unsurprisingly point out that God must be regarded as Holy - and suggest that there is nothing in the universe more important, nor could there be.
The ever sad Dawkins merely interprets this as hubris and vanity and is unable grasp the logic of the point.
With imperfect humanity - it would be as he claims. With an omnipotent Creator - different rules apply. If Christians are right about the existence of the Judaeo-Christian Supreme Being, then our position as to the nature of God makes perfect sense and his does not.
The problem here is that the likes of Dawkins will simply divert the argument and will point out that God advocated the 'butchering' of whole tribes without ever grasping the context.
Might I suggest to readers that if ever confronted with this type of argument, it may be countered by pointing out that the idolatry of these peoples was also linked heavily to child sacrifice.

It is not a particularly theological argument but one which might be much better accepted by non-believers in our modern age.

Photo: tomb of the type which might have contained the bodies of child sacrifices.

Archaeologists have also found 'jar burials' in Israel.

The entombed bones are from a site in modern Syria.