A.T. Robertson Commentary Matthew 26:70

"But he denied before them all, saying, I know not what thou sayest." — Matthew 26:70 (ASV)

I know not what thou sayest (ουκ οιδα τ λεγεις). It was an affectation of extreme ignorance (Bruce) that deceived no one. It was an easy and ancient dodge and easy subterfuge. Dalman (Words of Jesus, 80f.) suggests that Peter used the Galilean Aramaean word for know instead of the Judean Aramaean word which betrayed at once his Galilean residence.