Using the term brothers,
Paul is not referring only to the men in the church, but the whole church of Galatia. It is a common New Testament manner of speaking, and it is meant to emphasize the fact that Christians belong to the same family (see Galatians 4:4–7).
13 For you were called to freedom, brothers. Only do not use your freedom as an opportunity for the flesh, but through love serve one another.