After using the illustration of people who are invited to a feast, Jesus concluded with His explanation of WHY He was correct:
Lu 14:11 "For whoever exalts himself will be humbled, and he who humbles himself will be exalted."
Notice what Jesus said : "Whoever" exalts himself will be humbled. Jesus did not say, "Whoever exalts himself, unless he is right," or "Whoever exalts himself unless God told him to do it," or "Whoever exalts himself except those with decades of experience in leadership positions." Jesus taught that ANY Christian who exalts himself into a possition of leadership is going to get humbled.
So, how do you humble yourself? How do you know if you are humble? How do you not know that you aren't so proud that you think you're humble, when you're not? Despite all the jokes about "Humility and How I Obtained It," the Bible really does gives ways to become humble, and ways to tell whether or not you are humble.