Leonardo chose a completely blank expression for the man who had to attempt to mask his real reaction to Christ's announcement and pretend to be as shocked as the other apostles. While the other apostles tried to guess who would betray Christ, Judas knew it was none other than himself. Here he draws back from Christ, holds a money bag in his fist in reference to the bribe he accepted from the Romans and he reaches for the same bowl that Christ reaches for. They will both place their hands in this bowl, thus indentifying the betrayer. Behind him, St. Peter positions a knife as a subtle hint to the identity of the backstabber.