The NET Bible translates Galatians 2:9 this way:
and when James, Cephas, and John, who had a reputation as pillars, recognized the grace that had been given to me, they gave to Barnabas and me the right hand of fellowship, agreeing that we would go to the Gentiles and they to the circumcised.
The Nestle-Aland 27th edition of the Greek text shows four different variations in this verse for the reading and order of the three names James, Cephas, and John:
- James and John
- James, Peter, and John
- Peter, James, and John
- James, Cephas, and John (This is the one the editors conclude is original, and I concur.)
There are two central exegetical questions driving these variants, and answering them helps us both understand this passage and work through a better exegetical method.
Who was involved? This question deals with the Cephas/Peter interchange. (The absence of the name in the first reading occurs in only one manuscript according to NA27, and thus is very likely not original.) The standard response is that this is the apostle most commonly known as Peter; Cephas was an Aramaic version of his name, rather rare in the New Testament compared to Peter. So scribes very likely changed the rare name to the more common one to avoid confusion about who this was. This answer is acceptable, but it ignores one key fact: Right before this in the letter, in Galatians 2:7-8, Paul himself uses the name Peter to refer to this apostle. Why then would he immediately switch to Cephas in 2:9 and not continue using the name Peter as before? It could be stylistic variation, or it could be something in what Paul is asserting in each verse. To be honest I don't know, but we would not recognize any implications at all if we did not think through this problem more carefully than usual.
Is the order of the names significant? Because of the identity of Peter and Cephas as the same apostle in reality, the two basic options are "James, Peter, John" and "Peter, James, John." Assuming that the first option is original, why would a scribe change it? Because the order "Peter, James, John" is much more common when these three names are together, and Peter was well known as the lead apostle who should get top billing. Unfortunately this alteration does two things. First, it confuses who the James is. In the Gospels, the James in "Peter, James, John" is the apostle John's brother, James and John being the sons of Zebedee. In Galatians James is Jesus's brother, the leader of the church in Jerusalem. Second, it assumes that Peter should receive top billing, while the force of the story in Galatians indicates that James indeed was a major influence over Peter's actions, not vice versa. We are then forced to ask why James exerted the influence he did on this particular issue, that is, on the way Jews and Gentiles were interacting in the early church.
My point with this example is simply that thinking through text critical questions more carefully opens up exegetical insights that we might otherwise miss.