Man’s existence is vain. No matter what we do, there is no real meaning in it. Bad things happen to good people; good things happen to bad people. All the riches we work for in life are left to others when we die. Anything we build will eventually fall, and the greatest achievements of men are always reversed and torn down.
But there can be meaning in your life. God created man for a purpose, but man failed in that purpose. So God sent His Son into the world to pay for our failures, and when we trust in that payment, God gives our lives eternal meaning. This is how you escape a vain existence.