Robert Traill (By what Means may Ministers best win Souls), Works 1:241-242:
Take heed unto thyself, that thou be a lively, thriving Christian. See that all thy religion run not in the channel of thy employment. It is found by experience, that as it fares with a minister in the frame of his heart and thriving of the work of God in his soul, so doth it fare with his ministry both in its vigour and effects. A carnal frame, a dead heart, and a loose walk, make cold and unprofitable preaching. And how common is it for ministers to neglect their own vineyard? When we read the word, we read it as ministers, to know what we should teach, rather than what we should learn as Christians. Unless there be great heed taken, it will be found that our ministry and labour therein may eat out the life of our Christianity.