The heart is deceitful above all things, and it is exceedingly perverse and corrupt and severely, mortally sick! Who can know it [perceive, understand, be acquainted with his own heart and mind]? [Matt. 13:15-17; Mark 7:21-23; Eph. 4:20-24.]
But again he denied it falsely and disowned Him. And after a short while, again the bystanders said to Peter, Really, you are one of them, for you are a Galilean and your dialect shows it.
And at once for the second time a cock crowed. And Peter remembered how Jesus said to him, Before a cock crows twice, you will utterly deny Me [disclaiming all connection with Me] three times. And having put his thought upon it [and remembering], he broke down and wept aloud and lamented.