So, after the vision departs, Peter is summoned from Joppa to Caesarea to go see Cornelius. All of this we have already experienced in the last chapter, but Peter adds the note to his retelling that "six of these brothers also went with me" (11:12). That is, six members of the circumcision party witnessed all that Peter saw in that house, most particularly when the Holy Spirit fell on Cornelius and the rest of the Gentiles. In other words, Peter is saying, you finally cannot discount the evidence of some of your own people.
Peter wraps up his defense of the inclusion of the Gentiles in the community with his memorable words of 11:17.
If therefore God gave them the same gift (that is the Holy Spirit—cf. chapter 2) as to us who had believed in the Lord Jesus Messiah, was I powerful enough to prevent God (or "who was I to prevent God?")?
God clearly has in mind a reordering of the world as Peter knew it. And, just as clearly, God has in mind a reordering of the world as we know it.
In a nutshell, here is the issue of chapter 11: How can meals be holy yet shared with people we have been taught are unclean? And the answer is: The people you have thought to be unclean are not unclean—simple as that. So God says. The issue will not be laid completely to rest until the Jerusalem council meeting of chapter 15, but the fact is the issue has begun its settling the minute Peter walks into Cornelius' house, because Peter with his own eyes has witnessed the reality that "God has given repentance to life (or perhaps "conversion that leads to life") even to the Gentiles" (11:18). The Holy Spirit is still doing its work of giving life, and it, and God, are no "respecter of appearances."
Why can we not hear this amazing story? Why does it not inform daily our relationships with other religions, with people who are not like us? The answer to that is unfortunately simple: because we refuse to believe the fact that "God is no respecter of appearances."
When we deny the table to persons who are gay, we give the lie to this truth. When we refuse to allow gay persons to marry, we give the lie to this truth. When we refuse to ordain gay persons, we give the lie to this truth. Whenever we exclude anyone on the basis of "appearance," i.e. persons different in any way from us, we give the lie to this truth.
And when we decide that our way is the only way, we laugh in the face of the Holy Spirit who is forever blowing its own way, reordering our disordered world. Who are we to prevent God? Who indeed?