u/Darth_Armot

As far as I know, koine Greek was a colloquial form of Greek, different from more "formal" styles of Greek. In this sense, it seems reasonable to assume that Pauline epistles to be written in koine, since he wrote to close-knit communities.

On the other hand, there's Luke's gospel and Acts, which many scholars claim has a quite good style, but still is koine Greek. How common was to write literature in koine Greek? Was it an innovation to write "high literature" in koine?

If so, can we relate the early success of Christianity to the elevation of koine Greek? Similarly to many Medieval and Early Modern writers elevating their local languages over Latin.