New Defender's Study Bible Notes
2:7 Peter. It is interesting that Paul refers to “Peter” in Galatians 2:7-8, but calls him “Cephas” in Galatians 2:9, then “Peter” again in Galatians 2:11 (also Galatians 1:18; 2:14). The only other time Paul referred to Peter was in his first epistle to the Corinthians, but there he always called him Cephas (I Corinthians 1:12; 3:22; 9:5; 15:5). Both names mean “Rock”—Peter in the Greek, Cephas in Aramaic. His given name had been Simon (note John 1:42), but had been changed to Cephas (or Peter) by Christ. Paul obviously used the two names interchangeably.