Paul says that Peter’s withdrawal from table fellowship with the Gentile is nothing less that hypocrisy. The problem Paul has with Peter is his change of attitude and behavior after the visit from the “men from James.” The first verb Paul uses (shrink back) is a military term and has the sense of retreating to an “inconspicuous position” (Witherington, 154). In Acts 20:27 Paul uses the verb to describe what he did not do – he did not “shrink back” from preaching the gospel in Ephesus in the face of persecution.
The second verb (separate) has the sense of separating something into groups, as in separating sheep and goats in Matt 25:32. While this does refer to ritual purity (clean and unclean), there is an eschatological sense here as well. At the end of the age, the Lord will separate those who will enter the kingdom from those who will not. If I am right that the political and religious situation in Judea was becoming increasingly “apocalyptic,” it is possible that these “men from James” were encouraging a separation of the Jews and the Gentiles in anticipation of the coming judgment.
If this is the case, then perhaps Peter is afraid of real persecution by a zealous wing of the Jerusalem church. This is not a case of “the pastor is coming over, hide the beer bottles”! Peter and Barnabas may have withdrawn from fellowship to avoid a potentially violent reprisal from the “zealots” within Jewish Christianity. Paul himself sought to correct what he understood to be a false teaching about the messiah (Acts 8:1-3). It is impossible to be certain of the source of this persecution, but like pre-Christian Paul, this group was concerned about Diaspora Jewish Christian communities maintaining proper beliefs and practices.
While Peter is a hypocrite, Paul describes Barnabas as “led astray.” This is a different word which has the sense of being “carried away” by something. Perhaps Barnabas was fooled by the rhetoric of the “men from James.” Barnabas was originally sent to Antioch by Jerusalem and perhaps he was under some additional pressure by these men. His loyalty was to Jerusalem and was associated with the apostolic community since the earliest days (Acts 4). The Gentile mission is Paul’s commission, it is not Barnabas’s.
Peter’s actions, then, are out of character. He is not living out his beliefs nor is he keeping the agreement reached with Paul in Gal 2:1-10.