Where did Peter and the six Jews go after seeing Gentiles saved, and what happened to them?
After witnessing Gentiles saved, Peter and the six Jews returned to Jerusalem, not outward across the Roman Empire. There they were confronted for going to uncircumcised men, and Peter had to calm the critics by recounting what God had shown. Then the matter was forgotten for twelve years.
Les explains that normally you would think Peter and those six Jews, after seeing what could happen if Gentiles were approached with the Gospel, would have gone out across the Roman Empire, but they did not. They went back to Jerusalem, and when they got there they were called on the carpet for going to Gentiles, accused of going into men uncircumcised. Peter had to calm them down by saying God showed us He was in it, but then they all forgot about it. For twelve years there was no further mention of the Gentiles in the house of Cornelius being saved until Acts 15. Les sees the sovereign purpose in this: it came to Paul's defense in the Jerusalem council. If Peter had not remembered Cornelius, they never would have let Paul go back to Antioch with freedom to preach his Gospel; they would have plagued him every inch of the way.
And when there had been much disputing, Peter rose up, and said unto them, Men and brethren, ye know how that a good while ago God made choice among us, that the Gentiles by my mouth should hear the word of the gospel, and believe.