Purpose vs. Calling

I am giving you a warning now, today's post is going to be a English lesson. We were talking one day in our Bible study, and at the end we were given the task of finding the difference between purpose and calling. From what I found, purpose is the reason or motivation of why you are doing something, while calling is a job that you do. They are not interchangeable, and even I have been found guilty of thinking that they are one in the same. If you are Christian then our purpose is to bring glory to God. 1 Corinthians 10:31 says, "So, whether you eat or drink, or whatever you do, do all to the glory of God." That sentence describes our motivation behind everything we do, and it is to bring glory to God. Calling is the job that you do, weather it be a teacher, or an engineer, or the CEO of a company. The members of Casting crowns were called to work at their own churches, but they were also called to form a band and write such amazing songs for people. That is their calling. They do everything that they do to glorify God, and that is their purpose. 
I just want to make you more aware of the difference between these two words, because understanding the difference may help develope other understanding of God and yourself.

Dear Heavenly Father,
Help me to understand the difference in these two words. Help me to serve you in all I do, because that is my purpose. Help me understand what your calling is for me, because it is different for everyone. But knowing that I have my own individualized calling is refreshing to know. Thank you Lord for that. Amen.