Doctrine and Covenants 100: 4-6:

“Therefore, I, the Lord, have suffered you to come unto this place; for thus it was expedient in me for the salvation of souls.  

Therefore, verily I say unto you, lift up your voices unto this people; speak the thoughts that I shall put into your hearts, and you shall not be confounded before men; 

For it shall be given you in the very hour, yea, in the very moment, what ye shall say.”