Matius 26:34-35

26:34 Jesus said to him, “I tell you the truth, ¹  on this night, before the rooster crows, you will deny me three times.” 26:35 Peter said to him, “Even if I must die with you, I will never deny you.” And all the disciples said the same thing.

Matius 26:75

26:75 Then Peter remembered what Jesus had said: “Before the rooster crows, you will deny me three times.” And he went outside and wept bitterly. ² 

[26:34]  ¹ tn Grk “Truly (ἀμήν, amhn), I say to you.”

[26:75]  ² sn When Peter went out and wept bitterly it shows he really did not want to fail here and was deeply grieved that he had.