Therefore seeing we have this ministry, as we have received mercy, we faint not; (2 Corinthians 4:1)
There are trials common to both the pastor and the general body of Christ. The answer to the weariness and exhaustion of church ministry is an ever-increasing fervent love for Christ. All other motives and incentives prove to be vanity. The love of Christ must be the constraining mercy that drives the endurance of this pilgrimage and ministry.
All other motives than the constraining love of Christ in the heart soon lose their influence. There are no doubt other incentives, such as ambition, love of learning and desire for social influence, that may carry forward a minister for a while with apparent pleasure. But they will not stand the wear and tear of years of drudgery and trial. If the pastor who is chiefly actuated by these is successful, they will soon satiate; if he is not as successful as he expected to be, he becomes discouraged and disgusted with his office. If there is nothing more than these, the ministry soon becomes a miserable failure.
But when the love of Christ reigns in the heart supremely, it gives an impulse to the whole life that is ever steady and joyous. The wear and tear of toiling years will not wear it out. Sometimes there may appear only little success, but it has a faith that lays hold of the promises and is not discouraged. Through prosperity or adversity, among friends or enemies, in failing or continuing health, it moves steadily forward, impelled by an inward affection that cannot be quenched. Instead of years and trials wearing it out, it only grows stronger and stronger with the lapse of time. It constantly intensifies as more and more is seen of the love of Christ and the value of souls.
When earnest godliness reigns within it turns the whole life of the minister into a work of love.
 Thomas Murphy, Pastoral Theology. The Pastor in the Various Duties of His Office (Philadelphia,: Presbyterian Board of Publication, 1877), 55.