Question: are peter and cephas the same person?
Answer: Cephas means 'Rock' or 'Stone' in Aramaic, while Peter means much the same thing in Greek. As Peter was a Jew, it is natural that Paul use his Aramaic name, even when writing in Greek. ... The Gospel of Thomas refers to 'Simon Peter' twice, but never refers to 'Cephas' or just 'Peter'.