A.T. Robertson Commentary Galatians 1:2

"and all the brethren that are with me, unto the churches of Galatia:" — Galatians 1:2 (ASV)

All the brethren which are with me (ο συν εμο παντες αδελφο). The same phrase in Php 4:21 in distinction from the saints in verse 22. Probably the small company of travelling companions.

Unto the churches of Galatia (ταις εκκλησιαις της Γαλατιας). A circular letter therefore to all the churches in the province (both South Galatia and North Galatia if he really laboured there).