Galatians 2:13

Dissembled. Literally, “acted under a mask with [Peter],” that is, acted the part of hypocrites. Peter and these “other Jews” knew they were not doing right, but compromised themselves in order to avoid trouble with the Judaizers. They acted as they did in order to conceal their true sentiments from those who had come from Jerusalem. They pretended to side with the Judaizing brethren. If Paul’s charge of insincerity was true — and there is no reason to doubt that it was — Peter did well to remain silent, as he seems to have done. Nothing can be said in defense of his conduct, nor can it be excused.

Barnabas also. It must have been a great blow to Paul when his own familiar friend and co-worker succumbed to the pressure of popular opinion. Apparently, even strong Christian leaders are in danger of yielding their own convictions if sufficient pressure is brought to bear upon them.

Dissimulation. Literally, “hypocrisy,” “insincerity.”