Luke 22:31 And the Lord said Simon, Simon, behold Satan has desired to have you that he may sift you as wheat 32: But I have prayed for you that your faith fail not and when you are converted strengthen thy brethren. 33: And he said to him Lord I am ready to go with you both into prison and to death 34: And he said I tell you Peter the cock shall not crow this day before that you shall three times deny that you know me
 While Peter walked with Jesus, he swaggered around with a sword, rightly expecting to participate in the battle for the kingdom in which Messiah would win, and then sit on the throne of Israel. What Peter did not know, was though his expectation would indeed come to pass, it would be far into the future, and not during his lifetime.
Later, when Jesus did not initiate the battle Peter was expecting [to take the kingdom for himself], but was crucified and buried instead. This caused a temporary crisis of identity and faith for Peter. Even walking with Jesus daily, his motives had somehow gotten skewed along the way.
Are we examining our motives regularly?