Peter to the Cornelius:

Peter in Acts 10 went there against his will.  And didn’t even want to talk to Cornelius. (Who, by the way blessed Israel.  He was not an “unbelieving” Gentile, but a believing Gentile in the God of Israel.  Acts 10:22).

Acts 10:28  And he said unto them, Ye know how that it is an unlawful thing for a man that is a Jew to keep company, or come unto one of another nation; but God hath shewed me that I should not call any man common or unclean.

Notice Peter was still under the law still separating Jews from Gentiles.  Paul says we are not under the law and there is no separation between Jew and Gentile.  Rom 6:15, Gal 3:28 

 Also notice what Peter said to Cornelius:

 Act 10:35 But in every nation he that feareth him, and worketh righteousness, is accepted with him.  Peter’s teaching righteousness by works.  But Paul says it’s not by works we are saved: 

Rom 3:28  Therefore we conclude that a man is justified by faith without the deeds of the law.   Titus 3:5-6. 

Paul was the only bible character sent by Jesus to go to the Gentiles.   

Rom 11:13  For I speak to you Gentiles, inasmuch as I am the apostle of the Gentiles, I magnify mine office:

2Tim 1:11  Whereunto I am appointed a preacher, and an apostle, and a teacher of the Gentiles.

Compare Acts 10:35 with Titus 3:5.

So if you think Peter was going to Gentiles like Paul was, with the gospel of the grace of God like Paul was, think again, study it again.