From Douglas Wilson, on why, as pastors and preachers, we must spend ample amounts of time reading and studying:
Industriousness lies at the base of pulpit power. We use it here as equivalent to hard study . . . A strong preacher must keep his mental powers in working order. He must be a man of rigid, unremitted diligence. He must plough, and cross plough, and subsoil his own mind, that it may yield nourishment to other minds” (Fish, Power in the Pulpit, pp. 15-16).