You train, pass the test and are awarded a black belt. Your instructor hands you a new, shiny black belt. The sky opens up and you are bestowed black belt superpowers. You are invincible and fear no man.
This is NOT what happens when you receive your black belt. In fact, it is the complete opposite.
You train, pass the test and are awarded a black belt. Your instructor hands you a new, shiny black belt. The black belt is in your hands and almost immediately a thought stream enters your mind - I am not ready. I need more time. I should give it back.
Then you remember that black belt is the beginning. If you look up 1st Dan in the Dictionary of Martial Arts by Louis Frederic the word is described as Student. You wear your belt with the understanding that we all have more work to do learning and discovering.
It is about the training.