Why did Peter take other Jewish believers with him to Cornelius's house?
Peter was still a law-keeping Jew and had trepidation about the visit, so he took several fellow Jewish believers from Joppa to Caesarea as companions. Scripture does not specify how many, only that some brethren came with him. His law-keeping background explains his caution.
Les explains that Peter was still a good law-keeping Jew and had a lot of trepidation about going up to a Jewish household, so he took several of his fellow Jewish believers with him from Joppa to Caesarea. Scripture doesn't tell exactly how many, only that 'some of them, brethren,' came with him. This was about 10 years after Pentecost and the crucifixion, showing the law had not been set aside. Peter's vision in Acts 10:14, where the Lord said 'Rise, Peter, kill and eat,' involved unclean animals, and Peter's objection demonstrates he had not been set free from the law.
More Questions
How did Peter end up going to Cornelius's house in Caesarea?
God orchestrated Peter's meeting with Cornelius: Cornelius was prompted by God to send for Peter, and Peter, who was 80-90 miles away in Joppa, was brought to Cornelius's house by God's urging and miraculous working.
How many brothers came with Peter to Cornelius's house?
The Bible does not say exactly how many brethren came with Peter from Joppa, only that some of the brethren came with him.