Peter resisted the idea of a separation from Jesus. He felt willing even to die with Him if necessary rather than being parted from Him. Nevertheless Peter grossly underestimated his own weakness and what Jesus" death entailed. Peter spoke of laying down his life for Jesus, but ironically Jesus would first lay down His life for Peter (cf. John 10:11; John 10:15; John 11:50-52). Peter"s boast betrayed reliance on the flesh. Perhaps he protested so strongly to assure the other disciples that he was not the betrayer about whom Jesus had spoken earlier ( John 13:21). [source][source][source]
"Sadly, good intentions in a secure room after good food are far less attractive in a darkened garden with a hostile mob. At this point in his pilgrimage, Peter"s intentions and self-assessment vastly outstrip his strength." [1][source]
Mark recorded that Jesus mentioned the cock crowing twice, but the other evangelists wrote that He just mentioned the cock crowing ( Matthew 26:34; Mark 14:30; Luke 22:34). Mark"s reference was more specific, and the others were more general. [source][source][source]