"If our peculiarity went to the extent that we lived by every word that proceeds from the mouth of our Heavenly Father [see D&C 84:44], then we would indeed be a blessed people."
I noticed D&C 84:44 is referenced in connection with the statement.
So I asked myself, Where do I find "every word" that proceeds from the mouth of our Heavenly Father? And I found an answer in the words of the Old Testament Prophet Jeremiah.
I found a similar answer in God's words given through the Prophet Joseph Smith.
Both of these verses refer to "my servants." But who are these "servants?" Who are these "prophets?" I find answers to these questions in the Lord's preface to the Doctrine and Covenants.
In our day, we sustain Thomas S. Monson as "prophet, seer, and revelator and President of The Church of Jesus Christ of Latter-day Saints."
We also sustain his counselors in the First Presidency and the Twelve Apostles as "prophets, seers, and revelators."
God speaks in our day by the mouth of his servants the prophets. Those servants are the First Presidency and Quorum of the Twelve. Regarding their words, God has said:
God calls prophets to represent Him on earth. God's prophets teach His truth and help us understand the words of earlier prophets. When prophets speak for God, it is as if God himself were speaking. In that sense, they become God's mouth to us.
New revelation for the whole Church comes only through the Church President. He is "the prophet." However, he is not the only prophet on earth today. His two counselors are prophets. And the Twelve Apostles also have the calling of prophet.
I believe a Latter-day Saint who feels discouraged when apostles and prophets speak against that person's personal opinion should consider carefully the advice of a Pharisee named Gamaliel. He counseled moderation when criticizing the Apostles, "lest haply ye be found even to fight against God." (Acts 5:38-39.)