Matthew 16:24

Then said Jesus unto his disciples, If any man would come after me, let him deny himself, and take up his cross, and follow me.

Christ had just commanded Peter to get behind him; and immediately, Christ made the cross a necessary condition of discipleship. Not Peter, nor any other man, nor even Christ himself (as a man) can avoid it. Cross-bearing is widely misunderstood. It is not old age, poverty, taxes, illness, or bad weather, or any other discomfiture of life that comes unavoidably into the lives of men. It is the acceptance, for the sake of the will of God, of some burden or burdens, otherwise avoidable, but which are undertaken out of a pure desire to fulfill the Master's purpose. The centrality of the cross in Christ's religion was here affirmed by Christ at the very moment when one of his most beloved apostles had spoken against it.