Who are the God-fearing Gentiles depicted in Acts? Within this piece, I make the case that they were true old covenant believers who had not yet entered into the blessings of the new covenant. Upon entering the new covenant, they then received the gift of the Holy Spirit and the other blessings pertaining to the new age. However, this does not nullify the faith that they had beforehand.
The Household of Cornelius
Cornelius is introduced in Acts 10:2 as “a devout man who feared God with all his household, gave alms generously to the people, and prayed continually to God.” Despite this overwhelmingly positive description of a man with an active faith in God, many seem to portray Cornelius as something other than a genuine old covenant believer. This is most likely driven by a desire to make explicit faith in Christ the exact moment at which a person becomes a true believer. However, this reading goes against the straightforward introduction given in the passage, which clearly intends to portray Cornelius as a faithful believer.
Such a reading would also carry the implication that salvation is something which is earned rather than given as a free gift. In verses 4-5, God speaks to Cornelius and says that in response to his prayers and charitable gifts, he is to send for Peter, who will preach the Gospel to him. If the preaching of Peter is the occasion of him first becoming a true believer, then the implication is that God saved Cornelius on account of his good deeds (his prayers and charitable acts) and not by faith alone. However, if the transformation in question is simply about him being transferred into the new covenant, then this would not be an issue: God would simply be rewarding a faithful believer with new blessings on account of his loyalty.
One potential problem with this ‘existing believer’ reading is that Cornelius falls down and worships Peter upon seeing him (verse 25). However, in light of the fact that the Messiah came as a man, this is not a particularly surprising mistake for him to have made. Another potential problem is that when Peter recalls what happened to the Jerusalem church, he refers to Cornelius being “saved” along with his household (Acts 11:14). However, “salvation” in the new testament can sometimes refer to someone being delivered from the old covenant into the new covenant. It doesn’t necessarily imply that someone was not a true believer beforehand.
Lydia and the Ethiopian Eunuch
Another example of such an old covenant believer would be Lydia, first mentioned in Acts 16:11-15. She is introduced as “a worshipper of God”, which suggests that she was already a believer. The reason why she is often assumed not to have been a true believer is because the passage says that “the Lord opened her heart to pay attention to what was said by Paul”. However, the opening of a person’s heart does not necessarily indicate conversion. It could simply mean that God prompted her to carefully listen to what Paul had to say, on account of its importance.
Another example worth considering is the Ethiopian eunuch mentioned in Acts 8:26-40. He is said to have travelled to Jerusalem “to worship” and is discovered to be returning from Jerusalem with a copy of the book of Isaiah, which he is reading to himself. Again, some consider the eunuch to be a sort of “naïve believer” who didn’t really know God until Philip came to him with the gospel. Whilst it’s true that Philip discovers him puzzled over the meaning of a particular passage from Isaiah (v34), there is nothing in this which indicates a lack of true faith in God. Many believers, even today, struggle with how to read and interpret parts of the bible.
Nor is it merely already-believing Gentiles in view. Sometimes in Acts we encounter faithful Jews who are yet to come to an explicit faith in Christ. For instance, there is Apollos, who had already been “instructed in the way of the Lord”, and even “taught accurately the things concerning Jesus”! He would likely have been taught about Jesus by John the Baptist, since he is referred to as having been baptized by John (Acts 18:25). Then there are the twelve Ephesian men Paul encounters in Acts 19:1-7 who are referred to as “disciples” (v1). The only things that they are said to lack is specific knowledge about the identity of Jesus (v4) and the impartation of the Holy Spirit (v6). This suggests that they too were already faithful believers, who were simply yet to enter into the blessings of the new covenant.
book of Acts describes a crucial moment in salvation history. The moment when,
for the first time in history, God poured out his Spirit upon all flesh (Acts
2:17). In response to this message, many were converted and came to know God in
truth for the first time. However, there were many existing believers still
around who had not yet entered into this new covenant blessing. The book of
Acts documents this transitional period, a period in which many who already
knew the Lord came to a fuller knowledge of him through the gospel and were
filled with the Holy Spirit.
 Note that the apostle John makes a similar mistake, bowing down to an angel twice in the book of Revelation (19:10, 22:8-9). Each time the erroneous action happens though, it is quickly rectified.
 It is no coincidence that both of these instances of Jewish believers were disciples of John the Baptist. John’s fame was known throughout Israel and it would have been virtually impossible to be on the fence about him.