4:12 become as I am, for I also have become as you are. In order to bring the gospel to the Gentile Galatians, Paul had to leave behind the legal restrictions of the Mosaic ceremonial law that forbade Jewish interaction with Gentiles (1 Cor. 9:19–23). Paul became like the Galatians in freedom from the law, and he now encourages them to be like him in freedom from legalistic bondage.
You did me no wrong. Paul’s positive characterization of his previous relationship with the Galatian Christians (developed further in vv. 13–16) contains an implicit plea for good relations to continue. Paul’s depth of concern for the Galatians is evident throughout this section.