No man may intrude into the sheepfold as an under-shepherd; he must have an eye to the chief Shepherd, and wait His beck and command. Or ever a man stands forth as God’s ambassador, he must wait for the call from above; and if he does not so, but rushes into the sacred office, the Lord will say of him and others like him, “I sent them not, neither commanded them; therefore they shall not profit this people at all, saith the Lord.” Jeremiah 23:32
~Charles Spurgeon~
Lectures to My Students (Edinburgh, Scotland; The Banner of Truth Trust; 2008) p. 19.