Why does Paul refer to Peter as Cephas?

Maybe Paul calls Peter (Greek) Cephas (Aramaic) because his actions in Gal 2 denote an Old Testament mindset regarding Gentiles? ... read more

In John 1: 42 Jesus called Peter as Cephas. Jesus looked at him and said, “You are Simon son of John. You will be called Cephas” (which, when translated, is Peter). But throughout the Gospels, Peter was called as Peter and his books also called in his name I Peter and II Peter. read more

The legend on ‘Peter’s’ purported ossuary reads ‘Simon bar Jonah’ and we read in the Gospels that Peter was a surname - Aramaic Kephah - a Stone. Paul may have been referring to Peter when Peter acted like Peter and Cephas (Kephah) when he acted in a less sanctified manner. read more

But in AD 200, St Clement taught that Paul rebuked not Peter but one of the Seventy, another guy named Cephas. As support of this, Paul uses the name "Peter" in Galatians 2: 7-8, but shifts to "Cephas" in 2: 9 and following. read more