Then Jesus said to his disciples, "Whoever wishes to come after me must deny himself, take up his cross, and follow me. For whoever wishes to save his life will lose it, but whoever loses his life for my sake will find it. What profit would there be for one to gain the whole world and forfeit his life? Or what can one give in exchange for his life? For the Son of Man will come with his angels in his Father's glory, and then he will repay everyone according to his conduct. Amen, I say to you, there are some standing here who will not taste death until they see the Son of Man coming in his kingdom." (Mt 16:24-28)
Jesus asked his disciples to come after him. Following Jesus is not following a set of principles and rules. It is following a person. It is to walk the way that Jesus walked. It is to live the life of Jesus. Jesus lived a life of self-denial. (He emptied himself taking the form of a servant…). He carried the cross to Calvary. Every disciple has his journey to Calvary. And this journey is complete only by carrying the cross.
Life is a free gift of God. It is a gratuitous gift of God. Man can only be grateful to God for it. This is with regard to the earthly life. Jesus has come to provide life (a life in God). This life in God is gained only if one lived his earthly life for Jesus’ sake. So, like Jesus one has to deny his life and carry the cross and live out (lose) his life. In doing this one gains the life in God.
Everyone is repaid according to his conduct. Again the life live out here on earth becomes the criteria for the reward. One may gain everything on this earth and possess wealth etc but all of these are of no use when it comes to the reward of life. The conduct on which one will be judged is again on self-denial and the following of Jesus.