Acts 10:45

They of the circumcision. That is, the six Jewish Christians mentioned in Acts 11:12 as companions of Peter. Their astonishment is a testimony to the reality of the gift that Cornelius and his family received. Up to this point Christians had taken for granted that if Gentiles were to be Christians, they must first become full-fledged Jewish proselytes. The case of the Ethiopian eunuch baptized by Philip was probably not an exception to this. But Cornelius and his family were Gentiles, and Peter’s Jewish Christian companions were unable to understand how such could receive the gift of the Holy Spirit without first having become proselytes. Possibly an added reason for their astonishment may be found in the fact that some ancient Jews declared that in the days of the Messiah no proselytes would be received into Israel. Believing that the Messianic time had arrived, Peter’s companions may have been influenced in their thinking by such an exclusive attitude toward proselytes.

On the Gentiles. Peter’s Jewish Christian companions now saw a definite fulfillment of the apostle’s vision. Cornelius and his family, filled with the Holy Spirit, were proof that no man might henceforth call the Gentiles “common or unclean.” For Peter’s fellow Christians this evidence doubtless sufficed.