This is the story of the first non-Jew, called a Gentile, coming to Christ. The Jewish Christians did not think this was possible. They had spent their entire lives avoiding Gentiles and seeing them as enemies of God. Similar to what God had to do to convince Saul to trust Christ, God had to do something bold to convince Peter that Gentiles could be Christians. Just like Jews avoided Gentiles, they also avoided certain foods. God lets Peter know he can declare anything to be clean. Though Peter needed some convincing, he obeyed God and led a Gentile to Jesus.
This may seem like a strange transition to us today since most Christians are Gentiles. That’s how it is with change; once the change is made, it’s sometimes hard to remember why it was controversial. We live in a world that is changing and sometime we need to change to address the needs of a culture that has shifted. Changes like that can be controversial, but necessary. The central message of Jesus doesn’t change, but how we make him known does.