Matthew 26:73

And, after a little, the by-standers, coming forward, said unto Peter: Truly, thou also, art, from among them, for, thy very speech, maketh thee, manifest.

Judges 12:6

they said to him, Come now, say Shibboleth, and, if he said Sibboleth, and he could not take heed to speak in that manner, then laid they hold on him, and slew him at the fords of the Jordan, - and there fell, at that time, of the Ephraimites, forty-two thousand.

Nehemiah 13:24

and, their children, were one-half speaking the language of Ashdod, and understood not how to speak the language of the Jews, - but after the tongue of both people.

Luke 22:59-60

And, about one hour having passed, a certain other, began stoutly to insist, saying - Of a truth, this one also, was with him; for indeed he is, a Galilaean.

John 18:26-27

Saith one from among the servants of the High-priest, being, kinsman, of him whose ear Peter cut off, - Did not, I, see thee, in the garden with him?

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.

General references

Bible References

Surely

Luke 22:59
And, about one hour having passed, a certain other, began stoutly to insist, saying - Of a truth, this one also, was with him; for indeed he is, a Galilaean.
John 18:26
Saith one from among the servants of the High-priest, being, kinsman, of him whose ear Peter cut off, - Did not, I, see thee, in the garden with him?

For

Judges 12:6
they said to him, Come now, say Shibboleth, and, if he said Sibboleth, and he could not take heed to speak in that manner, then laid they hold on him, and slew him at the fords of the Jordan, - and there fell, at that time, of the Ephraimites, forty-two thousand.
Nehemiah 13:24
and, their children, were one-half speaking the language of Ashdod, and understood not how to speak the language of the Jews, - but after the tongue of both people.

General references

Proverbs 25:26
A fountain fouled, a spring spoiled, is a righteous man tottering before one who is lawless.