He penned those pathos-filled lines at the end of his missionary career because he had cultivated a ministering heart, and he cared. He refused to listen to his friends in England who pleaded with him not to go to that hostile land. No one has ever cultivated a ministering heart and lived to tell of a life of ease. Enlarge your heart, and you enlarge your experience of pain. The effects of these two kinds of hearts are drastically different.
Little hearts contribute nothing.
No one benefits. On the other hand, ministering hearts, though vulnerable, are hearts that posses the greatest joy, and leave their heart-print on the world. It has been said that the world is run by tired political leaders, that wars are won by exhausted generals, that peace is secured by tired diplomats, and that great legislation is accomplished by weary legislators. The reason for this is that such leaders are willing to put themselves out whenever necessary to accomplish their noteworthy tasks. John's Gospel informs us that Jesus was weary when he sat down by the well in the ancient town of Sychar in Samaria.