Most Jews thought that at best Gentiles could be used as dung to stoke the fires of hell. In many senses the Great Commission had been a failure. Although Jesus had said to go into the world after 10 years that had still been unfulfilled. It seems that the Jewish Christians had not broken out of the physical or theological walls of Jerusalem. Let me say that it is a good thing that he did otherwise Christianity would to this day have reminded a subsection of Judaism and not be the world religion that we know it is.
All people are to be associated with and evangelised.
This was jaw-dropping stuff. And the application of all this for us - Well as the Holy Spirit helped Peter overcome that which prevented him from fulfilling the Great Commission, so the Holy Spirit wants to help us overcome our barriers. The barrier of apathy I find that most people are not interested in playing their part in the Great Commission, for 101 reasons they have gone off the boil. The Holy Spirit comes to renew that heart for the lost. He comes to show us God's heart.