Yes—they were astonished because God was pouring out the Holy Spirit on Gentiles for the first time.
Acts 10:45 says the believing Jews who came with Peter were astonished because on the Gentiles was poured out the gift of the Holy Ghost. Les Feldick points out that these were not unbelieving Jews—they already believed Jesus was the Christ—but they had never seen anything like this before. God used the visible sign of speaking with tongues so these Jewish witnesses would know He was doing something completely new.
Acts 10:45 — This verse directly states that the believing Jews who came with Peter were astonished because the Holy Spirit was poured out on the Gentiles.
Acts 10:46 — This verse gives the audible proof that convinced the Jewish believers—they heard the Gentiles speak with tongues and magnify God.
Acts 10:28 — This verse shows Peter's own admission that it was unlawful for a Jew to associate with or enter the home of another nation, which explains why the event was so astonishing.
Acts 10:44-46 records the event. While Peter was still speaking, the Holy Ghost fell on all the Gentiles who heard the word. The Scripture then names the reaction of the Jewish believers: 'And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Ghost' (Acts 10:45). The next verse shows how they knew it had happened: 'For they heard them speak with tongues, and magnify God' (Acts 10:46). Earlier in the same chapter, Peter's own words reveal how remarkable this was. In the vision he said, 'Not so, Lord; for I have never eaten any thing that is common or unclean' (Acts 10:14). And when he arrived at Cornelius' house he said, 'Ye know how that it is an unlawful thing for a man that is a Jew to keep company, or come unto one of another nation; but God hath shewed me that I should not call any man common or unclean' (Acts 10:28). These verses show the legal barrier that the Holy Spirit's outpouring crossed.
Les Feldick stresses that the astonished Jews were not unbelievers. They were six Jewish believers who had come with Peter from Joppa, making a total of seven witnesses. They had already recognized that Jesus was the Christ, yet they were utterly astonished that Gentiles were hearing a salvation message and believing it. Les points out that this happened about ten years after Pentecost, and Peter was still observing the Jewish law's distinctions between clean and unclean. Peter regarded it as unlawful for a Jewish man to associate with or enter the home of someone from another nation. God had to show Peter that he should not call any person common or unclean. Les explains that God deliberately proved to these seven Jews that He was doing something totally new: saving Gentiles. He did this by pouring out the Holy Spirit on Cornelius and his household while Peter was still preaching, before they had been baptized. The proof was audible—the Gentiles spoke with other languages and magnified God.
Acts 10:45 calls them 'they of the circumcision which believed.' Les identifies these as six Jewish believers who came with Peter from Joppa, making seven witnesses in total. He stresses that these men were already believers—they had recognized that Jesus was the Christ—yet they were utterly astonished that Gentiles were hearing a salvation message and believing it.
Les says this was something that had never happened before. The Gentiles receiving the Holy Spirit was so shocking to the Jewish believers with Peter that they had never seen anything like it. The astonishment recorded in Acts 10:45 was because 'on the Gentiles was poured out the gift of the Holy Ghost.' In Les's words, 'Hey, that wasn't supposed to happen.' God was doing something totally different than had ever been done before.
Les points out that this took place about ten years after Pentecost, and Peter was still observing the Jewish law's distinctions between clean and unclean. When Peter saw the vision, he responded, 'Not so, Lord; for I have never eaten any thing that is common or unclean' (Acts 10:14). Later he told Cornelius' household that it was unlawful for a Jew to keep company with or come to one of another nation (Acts 10:28). Les notes that Peter felt trepidation about going, which is why he took several fellow Jewish believers with him to Caesarea.
Les contrasts the order in Acts 2 with what happened in Acts 10. Under Peter's preaching in Acts 2, Jewish hearers were told to repent and be baptized before they would receive the Holy Spirit. But in Acts 10, while Peter was still speaking, the Holy Spirit fell on all the Gentiles who heard the word—before they had been baptized and before they had heard anything of the Law. Les explains that God did this to prove to Peter and the six other Jewish witnesses that He was doing something totally new: saving Gentiles.
Acts 10:46 records that they heard them speak with tongues and magnify God. Les says God used the phenomenon of speaking in other languages as the proof. The Jewish believers heard the Gentiles speaking other languages, and that stopped Peter's preaching in its tracks. This was the evidence that the Holy Spirit had indeed been poured out on Gentiles.
Les shows that Jewish astonishment at Gentile conversion continued. When word reached the church at Jerusalem that Greeks at Antioch had believed and turned to the Lord, the Jewish believers' reaction was, in Les's paraphrase, 'Hey, what in the world's going on here? They can't be talking to Greeks. This is our business.' Even a man like Barnabas was needed to confirm that the grace of God had indeed reached Gentiles.
Peter's Law-Keeping and Gentile Separation
Les explains that about ten years after Pentecost, Peter still observed the Jewish law and regarded it as unlawful to associate with or enter a Gentile's home, which is why he took believing Jewish men with him to Caesarea.
Believing Jews Astonished at Gentile Salvation
These believing Jews—six men with Peter—were astonished that Gentiles were hearing the salvation message and believing it; God proved the new work by giving them other languages.
A First-Time Event: The Spirit Poured Out on Gentiles
Les says this had never happened before; the Gentiles receiving the Holy Spirit was so shocking to these Jews that they had never seen anything like it, and they knew by hearing them speak with tongues and magnify God.
Acts 10:45: The Astonishment Text
Les points to the exact verse that records the believing Jews' astonishment because the gift of the Holy Ghost was poured out on Gentiles.
The Six Believing Witnesses from Joppa
Les identifies the astonished men as the six believing Jews who came with Peter, making seven witnesses, and shows they were already believers in Jesus as the Christ before being astonished.
Holy Spirit Fell Before Baptism
Les notes the Holy Spirit fell on Gentiles while Peter was preaching, before baptism, and God used this to prove to Peter and six others that He was now saving Gentiles.
Acts 2 vs Acts 10: A New Order
In Acts 2, Jews had to repent, be baptized, and then receive the Spirit; in Acts 10, the Spirit fell on uncircumcised Gentiles while Peter spoke, before any baptism.
Jerusalem's Shock at Greeks Being Saved
Les shows the same astonishment later when the Jerusalem church heard Greeks at Antioch were turning to the Lord—Jews thought, 'They can't be talking to Greeks. This is our business.'
Acts 10:45: And they of the circumcision which believed were astonished, as many as came with Peter, because that on the Gentiles also was poured out the gift of the Holy Ghost.
Directly records the astonishment of the believing Jews who came with Peter.
Acts 10:46: For they heard them speak with tongues, and magnify God. Then answered Peter,
Explains how they knew the Holy Spirit had come—they heard the Gentiles speak with tongues and magnify God.
Acts 10:14: But Peter said, Not so, Lord; for I have never eaten any thing that is common or unclean.
Shows Peter's continued observance of Jewish clean and unclean distinctions.
Acts 10:28: And he said unto them, Ye know how that it is an unlawful thing for a man that is a Jew to keep company, or come unto one of another nation; but God hath shewed me that I should not call any man common or unclean.
Shows Peter's own statement that it was unlawful for a Jew to associate with or enter the home of another nation.
Acts 2:38: Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
Gives the order for Jews under Peter's Acts 2 message—repent, be baptized, then receive the Spirit.
Acts 10:44: While Peter yet spake these words, the Holy Ghost fell on all them which heard the word.
Records the moment the Holy Spirit fell on the Gentiles while Peter was speaking.
They were believers. Acts 10:45 calls them 'they of the circumcision which believed,' and Les says they were believers who recognized Jesus as the Christ. They had come with Peter from Joppa, so they were eyewitnesses of everything that happened in Cornelius' house.
In Acts 2, Jews were told to repent and be baptized first, and then they would receive the Holy Spirit. But in Acts 10, the Holy Spirit fell on the Gentiles while Peter was still speaking, before baptism. Les explains that God did this to prove to Peter and the six other Jewish witnesses that He was doing something totally new: saving Gentiles.
Acts 10:46 says they heard them speak with tongues and magnify God. Les points out that God used speaking in other languages as the proof, and it stopped Peter's preaching in its tracks.
Watch the Teaching: Why God Chooses the Weak: Lessons from Moses and the Cross