Some people always have an answer! Peter was, as usual, eager to protest his loyalty to the cause: and at face value he was speaking the truth.  He was a fisherman, and when Jesus called him away from his nets - he obeyed and followed.  However, he still had a home, wife and extended family (Matthew 8:14); and easy access to boats (Mark 3:9) and his old trade (John 21:3).  But his protest had a distinctly grasping edge, as the narrative includes more detail in Matthew 19:27: 'Peter answered him, "We have left everything to follow you! What then will there be for us?"'

Jesus unveils the reward for selfless service, but clarifies the qualifying criteria.  The rewards are only for service done for Jesus and for the Gospel - not for religious enthusiasm (as with the rich young ruler in Mark 10:17-22), and certainly not for bright ideas to help the Jesus-cause … Peter had already been rebuked for that (Mark 8:31-33).  The rewards for true service are, in this life, more than ample provision for our needs; and persecution as well (2 Timothy 3:12).  After that, a life with God that is undiluted for ever.  

Leaving what we cherish is not easy.  The rich young man chose to leave Jesus rather than leave his possessions.  Leaving home and all the relational benefits of a loving family is hard, but if the Lord calls then He will provide.  That was Abraham's experience (Hebrews 11:8-10), and Jacob's (Genesis 22:15).  The same is true of the Lord Jesus (Philippians 2:5-8) and would be true of every disciple who goes out with the gospel (John 15:18-21).  Gospel purpose is that Jesus' people will go out from where they are, to reach people who don't honour Jesus with the transformative message of salvation (1 Thessalonians 1:6-10).  However, it is the character as well as the sacrifice of comfort and security that is weighed.  Those who want to be first will be last and vice-versa, and those who want to have authority will have to be servants (Mark 9:35).  That may well have bitten into Peter's 'me-first' ego.

What we do, comes from what we are, from our character; and what we are is formed by our relationship with God and with others.  Peter's character had not yet been transformed by the Holy Spirit.  He behaved towards Jesus as a typical secular business person.  But Jesus was no more impressed by his assertive, on-message style, than by the rich young man (Mark 10:42-45).  Instead He was looking for a soft heart willing to serve without looking for reward.  This should remind us that whatever successful business style we have cultured, we need to be transformed by the Holy Spirit into servant-hearted believers if we are to pass an appraisal by Jesus (2 Corinthians 5:9-10).