Are there examples in scripture of God answering the prayers of unbelievers?
There are no examples we know of in scripture of unbelieving men or women praying to God and being heard. On the other hand, we do find examples of unbelievers who interact with God (in some form) like Cain, who knew of God but who lacked faith in God’s promises. These interactions are merely evidence of James’ comments regarding the acknowledgment of God but absent faith:
Nevertheless, the Bible states plainly that the “prayers” (i.e., petitions) of the unbelieving worlds are not heard by God, because unless we approach the throne of God by way of Jesus, we have no access to the Father:
These scriptures and others testify that no one may pray to (or approach) the Father except in the name of Jesus. Therefore, those who do not know Christ cannot be heard since they do not approach the Father through the Son. This is the plain teaching of the Bible.
Secondly, the Bible says that men and women are born enemies of God because of the sin they inherit from Adam, but by faith in Christ we are adopted as children of God: