When did Paul speak the truth to the Galatians and why would this make him their enemy?

Initially welcomed, the Galatians have become suspicious of Paul following the arrival of the Judaizers.¹ Paul asks if he is now their opponent rather than their friend. He does so in order to bring them to their senses.² Most likely he is referring to the truth he communicated to them when he was in their presence, though it is also possible that he is referring back to what he has written earlier in his letter.³