Holiness is required for usefulness
Study universal holiness of life.
Your whole usefulness depends on this, for
your sermons last but an hour or two; your life preaches all the
week. If Satan can only make a covetous minister a lover
of praise, of pleasure, of good eating, he has ruined your
ministry. Give yourself to prayer, and get your texts, your
thoughts, your words from God. Luther spent his best three hours
in prayer.
—Robert Murray McCheyne