"Then he called the crowd to him along with his disciples and said: 'If anyone would come after me, he must deny himself and take up his cross and follow me. For whoever wants to save his life will lose it, but whoever loses his life for me and for the gospel will save it.'" NIV translation
What does it mean to be a Christian ("come after me")? First, we must "deny himself" speaking of the fact that we must admit that we cannot work to better ourselves to a point where we become acceptable to God. Secondly, we do His will no matter what ridicule or shame we face. Those that prefer this life and the things of this world will miss eternity with Him.
"'What good is it for a man to gain the whole world, yet forfeit his soul? Or what can a man give in exchange for his soul? If anyone is ashamed of me and my words in this adulterous and sinful generation, the Son of Man will be ashamed of him when he comes in his Father's glory with the holy angels.'" NIV translation
A Christian will boldly stand up and say that we are saved only by the grace of God through the acceptance of the sacrifice of Jesus Christ. If we are ashamed to stand for His name now, we can be sure that He will not stand for us on the day of judgment. Without the Bread of Life which is Jesus Christ, we die.