"Two things you will find indispensable to profitable preparations for the pulpit: prayer and
toil. You must be a man of prayer. Prayer will give you thought, tenderness, and a power of feeling which nothing else can give. Sermons are heartless, lifeless things that are not elaborate with prayer. The difficulties of your work, and your own weakness invite you to your closet. If you look to yourself only, all is darkness, discouragement and despair. We have this treasure in earthen vessels, that the excellency of the power may be all of God. There is no substitute for Prayer. And you must consent to labour. There is no severer toil than the labours of the sacred ministry. Other men may rest; may retire from business and enjoy the fruits of their acquisitions; but there is no rest, no retirement for the minister of the gospel. The very Day of Rest of others, is a day of labour and solicitude with him. The duties of one Sabbath are scarcely fulfilled, and his thoughts are upon his preparations for another. And when he looks forward through life, he sees no end to his toil but in the grave. There is rest not until the battle is fought and the victory won."
-- Gardiner Spring, "Letter to a Young Clergyman," in Fragments from the Study of a Pastor (1838)