This is all good, but especially the last paragraph:
Only a flourishing spiritual life and a genuine walk in godliness with God will fortify the ordained teaching minister in times of discouragement.Robert Reymond, The God-Centered Preacher:Developing a Pulpit Ministry Approved by God, p. 117, 120
I sincerely believe that the ministerial failure, 'burnout' and 'dropout' about which we read and hear all too often today is to be traced directly to the minister's failure to maintain personal intimate fellowship with the triune God.
Because of the press of his myriad other ministerial duties, all too often he allows the cultivation of his spiritual walk with God--his training in godliness--to drop out of his daily vocational routine. Now mark well, dear pastors, the minister of God who eliminates this exercise from his daily round immediately places his ministry in peril.
...of this I am sure: you will know so many separate occasions of failure and discouragement in the gospel ministry that you will be no stranger to grief. The burdens are so great, the troubles so constant, the failures so painful, that unless you are personally thriving in your devotion to the Lord, delighting in his love and fellowship, enjoying intimacy with him in prayer, and generally having the gospel proven to you again and again in the secret places of your own heart, your ministry will not well endure the shocks that will come to it.