Matthew 26:73

After a little the bystanders came up and said to Peter, "To be sure, you are one of them too. Why, your accent betrays you!"

Luke 22:59-60

About an hour had passed when another man insisted, "That fellow really was with him. Why, he is a Galilean!"

John 18:26-27

Said one of the high priest's servants, a kinsman of the man whose ear had been cut off by Peter, "Did I not see you with him in the orchard?"

Treasury of Scripture Knowledge

Summary

And after a while came unto him they that stood by, and said to Peter, Surely thou also art one of them; for thy speech bewrayeth thee.

Bible References

Surely

Luke 22:59
About an hour had passed when another man insisted, "That fellow really was with him. Why, he is a Galilean!"
John 18:26
Said one of the high priest's servants, a kinsman of the man whose ear had been cut off by Peter, "Did I not see you with him in the orchard?"