In Analects, Confucius states the following:
At fifteen I set my heart on learning; at thirty I took my stand; at forty I came to be free from doubts; at fifty I understood the Decree of Heaven; at sixty my ears were attuned; at seventy, I followed my heart's desire without overstepping the line.
In ONE original post, explain what Confucius meant by this statement. (Be specific in your answer and explain each phrase thoroughly.)