“After a little while,

Bystanders came up.

They said to Peter.

‘Certainly,

You are also

One of them.

Your accent

Betrays you.’

Then he began

To curse.

He swore an oath.

‘I do not know this man.’”

μετὰ μικρὸν δὲ προσελθόντες οἱ ἑστῶτες εἶπον τῷ Πέτρῳ Ἀληθῶς καὶ σὺ ἐξ αὐτῶν εἶ, καὶ γὰρ ἡ λαλιά σου δῆλόν σε ποιεῖ.

τότε ἤρξατο καταθεματίζειν καὶ ὀμνύειν ὅτι Οὐκ οἶδα τὸν ἄνθρωπον.

This is almost word for word in Mark, chapter 14:70-71.  There is something similar in Luke, chapter 22:59-60, and John, chapter 18:26-27.  However, Luke did not have the curse or the oath, while John said that the man recognized Peter because he was a relative of the one whose ear Peter had cut off.  Matthew and Mark said that after a little while (μετὰ μικρὸν), some of the bystanders said to Peter (οἱ ἑστῶτες εἶπον τῷ Πέτρῳ) that he certainly was one of the followers of Jesus (Ἀληθῶς καὶ σὺ ἐξ αὐτῶν εἶ), because of his northern Galilee accent in his speech that betrayed him (καὶ γὰρ ἡ λαλιά σου δῆλόν σε ποιεῖ).  Then Peter began to curse (τότε ἤρξατο καταθεματίζειν).  He swore an oath that he did not know this man (καὶ ὀμνύειν ὅτι Οὐκ οἶδα τὸν ἄνθρωπον).  Thus, we have the 3^rd public denial of Jesus by Peter that can be found in all 4 gospels.  This apostolic leader had failed his first major test just as Jesus had predicted, despite his bombastic earlier outbursts that it would never happen.