Each Jewish synagogue tolerated a fringe of gentile believers, “devout” or “God-fearing” men, and it was among this fringe of proselytes that Paul made the bulk of his early converts to Christianity. Even the temple at Jerusalem possessed its ornate court of the gentiles. 
The gentiles were, from a moral standpoint, somewhat inferior to the Jews, but there was present in the hearts of the nobler gentiles abundant soil of natural goodness and potential human affection. 
Morality among the gentiles was not necessarily related to either philosophy or religion. Outside of Palestine it not always occurred to people that a priest of religion was supposed to lead a moral life.