Cornelius is described as “devout and God-Fearing” (verses 1-2). “Devout” is a word that indicates someone is devoted to a particular religion or god; a person who is “profoundly reverent” (BDAG). The word is used in Second Temple period literature to describe a godly man who is reverent to the God of Israel. (Simon the Just, in Josephus, Anitq. 12.43, for example.)
The description of Cornelius as a God-Fearer may mean he was a Gentiles who were near-converts to Judaism. When Luke used the term “God-fearer” he likely has in mind Gentiles who worshiped God in the Synagogue without taking on all the Jewish boundary markers. Julius Scott provides the more or less standard definition of a God-Fearer: “an unofficial class of Gentiles who stopped short of becoming full proselytes but were permitted limited participation in Jewish worship” (JETS 34 (1991): 478).
This consensus view was challenged in 1981 by A. T. Kraabel. He examines the archaeological evidence from synagogues available at that point in time and concludes that there was not a class of Gentiles worshiping alongside Jews in Diaspora synagogues. For example, after examining 100 synagogue inscriptions, not one of them mentioned God-fearers, although the term theosebos appears with a Jewish name on ten occasions (116). Based on his reading of the archaeological evidence, Luke created this class of “near convert” for theological reasons. “It is a tribute to Luke’s dramatic ability that they have become so alive for the later Church, but the evidence from Paul’s own letters and now from archaeology makes their historicity questionable in the extreme” (120).
But it is likely that evidence for God-Fearing Gentiles can be found in the Synagogue inscription from Aphrodisias. This inscription was published in the mid-1960s, this register dates to the third century and lists Jews (with Hebrew names) and God-worshipers (with Greek names, none have Jewish names) in separate columns. Furthermore, the Roman satirist Juvenal mocked Gentiles who kept Jewish food laws as“Sabbath-fearing” (Sat. 14.96-106). Kraabel’s evidence does not include very many Synagogue inscriptions from the first century, in fact, there is only one in his list (in Delos). This is not surprising since there few first century Diaspora synagogues have been excavated.
In short, there is Kraabel is right to warn scholarship away from thinking that there a large percentage of synagogue members were God-Fearing Gentiles. He is right, that this was not a technical term or official class, as it sometimes appears in popular descriptions of Second Temple Period synagogues. Yet he goes to far by suggesting that there were no Gentiles who worshiped in Diaspora synagogues. Likely there were God-Fearing women in most Synagogues, perhaps fewer men. These Gentiles may be a primary reason why Paul began ministry in a new town by preaching in the Synagogue that the Gentiles can be right with God apart from Law.
A. T. Kraabel, “The Disappearance Of The ‘God-Fearers’” Numen 28 (1981):113-126.
J. Reynolds and R. Tannenbaum, Jews and God-fearers at Aphrodisias: Greek Inscriptions with Commentary (Proceedings of the Cambridge Philological Association Supplement 12; Cambridge Philological Society 1987).