It is not clear if Paul is referring to what he said to the Galatians on his earlier visit to them Acts 13:2 – 14:28) or that which he said in the previous verse.1 Most probably it has to do with his earlier visit.2 The Galatians heard the true gospel from Paul and he warned them at that time that they must not substitute it for another that includes works or calls for circumcision and obedience to the Mosaic law.
9 Nous l'avons dit précédemment, et je le répète à cette heure: si quelqu'un vous annonce un évangile s'écartant de celui que vous avez reçu, qu'il soit anathème!