It is Peter, not Paul, who is the image of a believer in the Gospel of Mark. Peter is the model for those who sin again and again because of personal weakness or fear, for those who do not understand or give priority to their own ideas and agendas. Peter is also the model for those who only slowly and painstakingly come to understand the meaning of Jesus, the poor and crucified one, risen from the dead. Peter is the one who, when called, follows, stumbles, and then becomes a stumbling block for the others as he betrays Jesus. Peter is slow to realize that he must repent and that he needs massive forgiveness. In the end, after Jesus' resurrection, he finally "gets it," thanks to the power of the Spirit.
— Megan McKenna, On Your Mark