If anyone is ashamed of me and my words in this unfaithful and sinful generation, the Son of Man will be ashamed of him when he comes in the Father's glory with the holy angels around him. Mark 8:38, Phillips.
I will never forget the burning tears that flowed down my red cheeks as my teacher spoke to me. As an impulsive fifth grader I had shoved or otherwise annoyed a classmate, who had yelled at me in retaliation. My teacher probably didn't know that I practically worshiped her. So when she spoke words of discipline she never sensed how deeply they cut. "I am so ashamed of you," she said.
Some of those same feelings want to surface when I read that, under certain circumstances, Jesus would be ashamed of me. It seems somehow out of character for Him to employ such a crushing approach in an attempt to draw me upward. If He would die for me while I am still a sinner; if He would offer me the robe, ring, and sandals of sonship while I still smelled of the pig farm, then why would He ever turn toward me and say "I am ashamed of you"?
The feelings of being ashamed often arise when two value systems are in conflict. For example, I have declared myself to be a Christian. But in my heart I am not really sold on Jesus, not fully persuaded of His lifestyle. Among my more worldly friends I will be ashamed to act as a Christian. Among my Christian friends I will be ashamed of my worldly leanings.
Shame vanishes when I am proud of Jesus. There is no occasion when all my actions are in perfect harmony with my spiritual values and when I am comfortable in His presence with my present actions. And since Jesus is also a thinking, valuing Person, this flows both ways. For Jesus to be "ashamed" of me is to acknowledge that we are out of phase with each other--that we are not at peace in each other's presence.
When Jesus comes in the clouds of glory to take people home to live with Him forever, He who always tells the truth must take a position about who is really ready to live at peace with Him. He who felt no personal embarrassment at eating dinner with prostitutes does not have His personal identity at stake. Rather, He has the happiness of the eternally redeemed at stake.