Albert Barnes Commentary Galatians 2:13

"And the rest of the Jews dissembled likewise with him; insomuch that even Barnabas was carried away with their dissimulation." — Galatians 2:13 (ASV)

And the other Jews. That is, those who had been converted to Christianity. It is probable that they were induced to do this by Peter's example, as they would naturally regard him as a leader.

Dissembled likewise with him. They dissembled or concealed their true sentiments. That is, they attempted to conceal from those who had come down from James the fact that they had been in the habit of associating with the Gentiles and of eating with them. From this it would appear that they intended to conceal this wholly from them, and that they withdrew from the Gentiles before anything had been said to them by those who came down from James.

Insomuch that Barnabas also was carried away, etc. Concerning Barnabas, see the notes on Acts 4:36.

Barnabas was Paul's intimate friend. He had been associated with Paul in very important labours; and the fact, therefore, that Peter's conduct was causing such an unhappy influence as to lead even a man as worthy and good as Barnabas into hypocrisy and error, made it the more proper that Paul should publicly notice and reprove Peter's conduct. This was undoubtedly a painful duty, but the welfare of the church and the cause of religion demanded it, and Paul did not shrink from what was so obvious a duty.