D&C 11-18

In revelation to Hyrum Smith, Joseph Knight, David, John, & Peter Whitmer, and whosoever is willing, the theme is basically the same, the thing that is of most worth is to keep his commandments and declare repentance and work to bring forth and establish Zion. But before we can declare repentance and establish Zion, we must "first seek to obtain my word, and then shall your tongue be loosed; then, if you desire, you shall have my Spirit and my word, yea, the power of God unto the convincing of men." (Doctrine and Covenants Section 11:21)

It is the Spirit "which shall enlighten your mind, which shall fill your soul with joy; (Doctrine and Covenants Section 11:13). As we receive the Spirit, we must put our "trust in that Spirit which leadeth to do good—yea, to do justly, to walk humbly, to judge righteously;"(Doctrine and Covenants Section 11:12)

And to Oliver Cowdery as he received the word - "2 Behold, I have manifested unto you, by my Spirit in many instances, that the things which you have written are true; wherefore you know that they are true.
3 And if you know that they are true, behold, I give unto you a commandment, that you rely upon the things which are written;
4 For in them are all things written concerning the foundation of my church, my gospel, and my rock.
5 Wherefore, if you shall build up my church, upon the foundation of my gospel and my rock...
(Doctrine and Covenants Section 18:2 - 5)