The times of ignorance

i) Gen 4-11 is skimpy regarding the postlapsarian history of humanity. To some degree this can be supplemented by Acts 14:16-17 & 17:30:

16 In past generations he allowed all the nations to walk in their own ways. 17 Yet he did not leave himself without witness, for he did good by giving you rains from heaven and fruitful seasons, satisfying your hearts with food and gladness.”

30 The times of ignorance God overlooked, but now he commands all people everywhere to repent

As one commentator explains:

[Paul] is not claiming that their ignorance and rebellion were ignored by God and without consequence (cf. 17:30-31 note). Since, in biblical teaching, his involvement in the life of Israel was for blessing and salvation, his abandonment of the nations "to go their own ways" (the plural tais hodois suggests a diversity of options) was a curse and an anticipation of final judgment (cf. Rom 1:18-32; 2:1-11) God did not provide the nations with special revelation, such as he gave to Israel, and did not directly offer them a way of salvation, though Israel was always meant to be a source of blessing to the nations (cf. Gen 12:3).

They belonged to the times of ignorance. God did not approve this ignorance, nor did he suppress it or bring retribution, as he might have. He "overlooked" it (hyperidon, "disregarded"; cf. 14:16 note). We might compare Rom 3:25, where Paul says that in his forbearance, before the coming of Christ, God had "left the sins committed beforehand unpunished". D. Peterson, The Acts of the Apostles (2009), 410,502.

The basic idea is that God didn't intervene in the history of most people-groups in the same way he did in the case of the Jewish people. Using ancient Near Eastern and Greco-Roman culture, which is Paul's immediate frame of reference, that alludes to the development of pagan polytheism, idolatry, necromancy, sorcery, astromancy, human sacrifice, &c. And beyond Paul's frame of reference, we might include animism. 

The distinction isn't merely before the new covenant. For even after the new covenant, it takes centuries for that to disseminate. 

ii) This doesn't necessarily mean God never revealed himself to individual gentiles or interceded on their behalf. We have biblical examples of pagans who receive revelatory dreams. There's also the dramatic example of the Magi (Mt 2). 

iii) Admittedly, these are mentioned in cases where the lives of Jews and gentiles intersect. Perhaps God never intervened except in cases where the two groups overlap. Or perhaps God did intervene in other cases, but the only occasion for Scripture to mention divine intervention in the lives of pagans is where their lives impinge on the lives of Jews and Christians. For instance, it would be unintelligible to the original audience for Scripture to refer to Indian tribes in North and South America.  Moreover, that would take the eye off the unique role of the Jewish people in the plan of redemption. 

iv) But even if (ex hypothesi) God sometimes intervened in the lives of individual gentiles, by way of private revelation, miracles, answers to prayer, that's different from public revelation to a people-group, or Exodus-style miracles on behalf of a people-group. 

v) This goes to the question of whether God preserved a continuous remnant between the Fall and the call of Abraham. Perhaps not. Maybe knowledge of the one true God was lost for a time. Maybe God allowed that to lapse. 

vi) However, this also goes to the question of whether peaceful coexistence was possible between pagans and adherents of the true faith. It's my impression that urbanization fostered religious intolerance. By that I mean, city-states typically have an official religion with a priesthood and cultus. The patron god of the city or the kingdom. 

Although that allows for syncretism, where residents are free to practice their folk religion, residents are required to participate in the cultic life of the city-state. I'm thinking, not merely of Egypt and Mesopotamia, but Aztecs, Incas, and Maya. 

It may be that in more pastoral societies, characterized by nomads or hunter-gatherers, there's greater tolerance for religious pluralism. There's not the same pressure to conform to a state religion.