It’s not surprising, then, that the oldest excavated Christian church – the third-century house-church from Dura-Europos, Syria – would have featured an image of David on its walls. The surprising part is which episode of David’s many-wiled life these Christians chose to depict: on the main panel of the southern wall of its baptistery, this community commemorated David by showing him poised to slay the fallen Goliath.That doesn't surprise me. Giants are cool. (But Professor Peppard's evaluation of the image is more sophisticated.)
There are many, many past PaleoJudaica posts on Dura-Europos. Start here (with more from Michael Peppard) and follow the links.