John Gill Commentary Mark 14:68

"But he denied, saying, I neither know, nor understand what thou sayest: and he went out into the porch; and the cock crew." — Mark 14:68 (ASV)

But he denied
That he was with Jesus, or a disciple of his:

saying, I know not; Jesus of Nazareth: neither understand I what you
sayest ;
about him, and of being with him: the last phrase, "neither understand I", is omitted in the Syriac and Persic versions:

and he went out into the porch ;
adjoining to the palace, to consider what to do, being surprised and confounded at such a challenge:

and the cock crew ;
the first time, being about midnight; and yet he took no notice of it, nor remembered what Christ had but a few hours before said to him: or if he did, he might hope he should not meet with another attack, or he should have more courage and strength than to deny a second time.