D&C 32

In an earlier revelaton to the elders of the Church, the Lord said -

"...ye are called to bring to pass the gathering of mine elect; for mine elect hear my voice and harden not their hearts..."  (Doctrine and Covenants   Section 29:7)

It was and continues to be message to the missionaries of the Church -

"...I say unto you that ye are chosen out of the world to declare my gospel with the sound of rejoicing, as with the voice of a trump. 5 Lift up your hearts and be glad, for I am in your midst, and am your advocate with the Father; and it is his good will to give you the kingdom.

6 And, as it is written—Whatsoever ye shall ask in faith, being united in prayer according to my command, ye shall receive."  (Doctrine and Covenants  Section 29:4 - 6)

The promise is that He will be in the midst of the missionaries and an advocate to the Father.  As Ziba Peterson was called to the work, again the Lord emphasized -

"...I myself will go with them and be in their midst; and I am their advocate with the Father, and nothing shall prevail against them."  (Doctrine and Covenants  Section 32:3)

This promise must serve and provide a great deal of comfort to missionaries and their parents.  The Lord then provides this instruction to missionaries -

"And they shall give heed to that which is written, and pretend to no other revelation; and they shall pray always that I may unfold the same to their understanding.
5 And they shall give heed unto these words and trifle not, and I will bless them..."  (Doctrine and Covenants  Section 32:4 - 5)

It becomes clear that it is to be by the Spirit and the scriptures that should be that which they should preach.