D&C 75

To those who were called to preach the gospel, the Lord commanded -

"...proclaim the things which I have commanded them—
10 Calling on the name of the Lord for the Comforter, which shall teach them all things that are expedient for them—
11 Praying always that they faint not..." (Doctrine and Covenants Section 75:9 - 11)

We have read much that -

"...the Spirit shall be given unto you by the prayer of faith; and if ye receive not the Spirit ye shall not teach." (Doctrine and Covenants Section 42:14)

Prayer of faith and teaching by the Spirit are two essential requirements to preach. One cannot be accomplished without the other. This principle is even recognized by one that is not of my faith as he comments -

"What is preaching without praying! Sermons are but pulpit performances, learned essays, rhetorical orations, popular lectures, or it may be political harangues, until God gives, in answer to earnest prayer, the preparation of the heart, and the answer of the tongue. It is only he who prays that can truly preach. Many a sermon that has shown no intellectual genius and has violated all homiletic rules and standards has had dynamic spiritual force. Somehow it has moved men, melted them, moulded them. The man whose lips are touched by God’s living coal from off the altar may even stammer, but his hearers soon find out that he is on fire with one consuming passion to save souls" (Arthur T. Pierson, The Fundamentals, Vol. IX., p. 67).” (Commentary, p. 435.)

It is only when -

"...he that preacheth and he that receiveth, understand one another, and both are edified and rejoice together." (Doctrine and Covenants Section 50:22)

One more thought. The Lord gave this charge to those that have not been sent forth to preach -

"...that it is the duty of the church to assist in supporting the families of those, and also to support the families of those who are called and must needs be sent unto the world to proclaim the gospel unto the world." (Doctrine and Covenants Section 75:24)

The Lord makes it clear that all the saints have a economic responsibility to support the families of those that are called on missions. We are all in this work together.