Why was Peter's vision important?

A:

In Acts 10:10-20, Peter had a vision in which he was called upon to eat non-kosher food, which he soon realised was a call to preach to the gentiles. Soon afterwards he was the leading supporter in Jerusalem for this cause.

This vision is important because it counters Paul's earlier claim that he was called by God to preach to the gentiles, and that Peter had resisted doing so, even eating separately from Paul's gentile converts when they ate non-kosher food (Galatians 2:12).

In my view the purpose of Acts was to compare Peter and Paul, in order to show Peter to be the greater apostle. George Wells (Evidence for the Historical Jesus) quotes A. J. Mattill as saying that the dominant view of Acts' presentation of Paul is that in Acts and the epistles there are two Pauls, the historical Paul of the authentic epistles and the legendary Paul of Acts.