The story of the denial of St. Peter depicted here follows the text of Matthew 26:69-70; "And as Peter was below in the courtyard, one of the maids of the high priest came; and seeing Peter warming himself, she looked at him and said, 'You were also with the Nazarene, Jesus.' But he denied it saying, 'I neither know nor understand what you mean.' And immediately, while he was speaking, the cock crowed. . . . And Peter remembered the words of the Lord, how he had said to him, 'Before the cock crows today, you will deny me three times'. And he went out and wept bitterly."
The story is also related in two other gospels: Mark 14:66 and Luke 22:54-62. The nocturnal fire as the setting is mentioned in all three accounts.