Quitting is not an option when one is fully committed to the Lord. Jeremiah was a man just like you and me and Jeremiah had as much reason to quit on the Lord as any of us. He was called by God to preach to the people of Judah and tell them that God was about to withdraw His protection.
However the people pursecuted him and he found himself in jail or the stocks on several occassion. At moments like that He felt torn between honoring God and giving up on serving Him. But in the end he couldn't quit on God. Hebrews 12:1 encourages us to run with endurance the race of life that is before us, by fixing our lives on Jesus the author and perfector of our faith. Stay the course, serve the Lord.