Having grown up in a predominantly Jewish neighborhood, I learned firsthand of the old Jewish attitudes about associating with Gentiles. Most of my friends were Jewish; they didn’t see any problem with us, and for most part, their parents were fine with us, but the grandparents were a different story. From time-to-time, I would be invited into their homes for a meal, and when a grandparent was present, the experience could be a bit awkward. My friends used quite a few Yiddish expressions, as their parents did, and as time went by, I picked up quite a bit and by the time I was learning to drive a car, I spoke Yiddish better than some of my friends did; I learned that this would get the attention of a grandparent who didn’t think a goy should be at the dinner table.
I would simply speak to them in (imperfect) Yiddish, and they would invariably decide that I was OK for a Gentile, and I became an “honorary” Jew in several families.
When the believers back in Jerusalem heard about Peter’s visit to Cornelius, they wanted an explanation: How could he even consider sitting down with goyim (not so nice term for Gentiles i.e. ‘dogs’)?
Peter gave his answer in 11:4-11, telling them about the vision God had given, about how they were not to call anything unclean that God has made clean. Then, he recounts his visit to Cornelius:
“As I began to speak, the Holy Spirit came on them as he had come on us at the beginning. Then I remembered what the Lord had said: ‘John baptized with water, but you will be baptized with the Holy Spirit.’ So if God gave them the same gift he gave us who believed in the Lord Jesus Christ, who was I to think that I could stand in God’s way?” (11:15-17)
What could they say to that?
When they heard this, they had no further objections and praised God, saying, “So then, even to Gentiles God has granted repentance that leads to life.” (11:18)
Luke doesn’t actually say so, and I could be wrong, but I think I detect a little bit of astonishment in their reaction, for it is clear enough that not even Peter had previously considered that Jesus had saved all Mankind on the cross, that He had intended the Good News to be for all people, if “all people” included Gentiles. Yet to his enduring credit, when the time came for God to make this clear, Peter didn’t hesitate to accept God’s plans.
And so the Jewish believers of Jerusalem accepted the Gentiles… well, sort of. This issue would remain controversial throughout the first century, and even into future centuries, and would become manifest in a variety of rather unattractive ways on both sides of the divide.