The word ‘ashamed’ translates the Greek which comes from disfigurement. The idea behind the word is this: if a person is deeply disfigured, then that person would naturally want to hide his features or her features in some way.
Even though we are surrounded by a society and a generation which revels in sin and adultery and LGBT values; even though it's going to be rough for us, to be ashamed of him and his words is so grave, is so insulting, is so treacherously ungrateful, that Christ says, ‘Of him also shall the Son of Man be ashamed.’ Such a person must surely be a nominal Christian, not a true Christian. So if that's my position, and I insist, ‘It doesn't represent me’, then I better get out of it quickly. I had better pray for deliverance from it, and represent him as I should. I better let it be known that I am his, and speak for him, and pray for the lost and seek to reach them with the gospel. If Christ would be ashamed of me because I'm ashamed of him, I must be nowhere. So I’ll reverse my way of life, and I'll ask him to help me, and I will show this proof of conversion also.
Do you have in you the mark of salvation? Not necessarily a condition of salvation, but a certain mark that you're a willing cross bearer, that you're not trying to save the old life; that you readily take up the new life, and that you represent him? These are wonderful signs and seals of assurance.