Peter’s choice of the upside-down cross was the truest symbol of unentitled devotion because he refused to exalt himself even in imitation of Christ, thus representing His completely self-denying identity. The only response of a true disciple when confronted with the cross of Christ is to lose all sense of pride in your own glory, to release your earthly expectations and take up your cross and follow Him in the pattern of unconditional lay-down-your-life love.
I would purport that it was not the prodigal son’s request to obtain his inheritance early OR even that he squandered it all. Rather it was that upon receiving his inheritance, the younger son went far away from his father’s house to live for himself; and by doing so, he effectively severed all relationship with his father. Therefore we see that the true sin of the prodigal son was that he quantified his sonship in terms of the sum of money to which he was entitled by birthright and failed to recognize the true value of his sonship – the relationship with his father.
What did Jesus do in response to his equality with God? He laid down his right to be God. Jesus was the only person truly entitled to equality with God, and yet He chose to separate Himself from that reality by literally dying to Himself and thus denying His own right to exert His Godlike power and authority. Our Lord traded His divine entitlement for the will to die. Jesus’ death was a fulfillment of the true character of God, a tangible way to tell the world that the true divine instinct does not rise towards power and preservation but denies the tempting urge to grasp at it. God sent the person of Jesus to be the complete and perfect imprint of His own self-denying identity.
At its root, almost every problem that humanity has wrestled with since the dawn of time boils down to the glorification – or deification – of the self in some way shape or form. Jesus came to save us from our self-centered world by demonstrating selfless love by laying down his life in thought, motive, action, word and – ultimately – his very death. Therefore, the only antidote to our current state of self-preoccupation is complete and utter SELF-DENIAL, which is to “deny yourself, take up your cross,” and follow the example of the only person who ever truly died to Himself.