The LDS Church Doesn't Claim to Have all Truth or Goodness

-

It is our duty and calling, as ministers of the same salvation and Gospel, to gather every item of truth and reject every error. Whether a truth be found with professed infidels, or with the Universalists, or the Church of Rome, or the Methodists, the Church of England, the Presbyterians, the Baptists, the Quakers, the Shakers, or any other of the various and numerous different sects and parties, all of whom have more or less truth, it is the business of the Elders of this Church (Jesus, their Elder Brother, being at their head) to gather up all the truths in the world pertaining to life and salvation, to the Gospel we preach, … to the sciences, and to philosophy, wherever it may be found in every nation, kindred, tongue, and people and bring it to Zion (Discourses of Brigham Young, 248, quoted in "Chapter 2: The Gospel Defined", Teachings of Presidents of the Church: Brigham Young, (1997), 14–20)

-

Freedom is based on truth, and no man is completely free as long as any part of his belief is based on error, for the chains of error bind his mind. This is why it is so important for us to learn all the truth we can from all the sources we can. We need particularly to search the scriptures, for in them are the words which, if accepted and lived, will lead us to eternal life. (“Ye Shall Know the Truth”, N. Eldon Tanner, Apr 1978)

-

We do not claim that others have no truth. The Lord described them as having “a form of godliness.” Converts to the Church may bring with them all the truth they possess and have it added upon. ("The Only True Church", Boyd K. Packer, Oct 1985)

-

Let me say that we appreciate the truth in all churches and the good which they do. We say to the people, in effect, you bring with you all the good that you have, and then let us see if we can add to it. That is the spirit of this work. That is the essence of our missionary service (meeting, Nairobi, Kenya, 17 Feb. 1998, Quoted in "Excerpts from Recent Addresses of President Gordon B. Hinckley", Ensign Aug 1998).

-

Is it possible to find truth? 

The purpose of my remarks is to proclaim the joyful message that God Himself—the Lord of Hosts who knows all truth—has given His children the promise that they can know truth for themselves. 

... 

My dear friends, here is a fairly straightforward experiment, with a guarantee from God, found in a book of ancient scripture available to every man, woman, and child willing to put it to the test: 

First, you must search the word of God. That means reading the scriptures and studying the words of the ancient as well as modern prophets regarding the restored gospel of Jesus Christ—not with an intent to doubt or criticize but with a sincere desire to discover truth. Ponder upon the things you will feel, and prepare your minds to receive the truth. “Even if ye can no more than desire to believe, let this desire work in you … that ye can give place for [the word of God].” 

Second, you must consider, ponder, fearlessly strive to believe, and be grateful for how merciful the Lord has been to His children from the time of Adam to our day by providing prophets, seers, and revelators to lead His Church and help us find the way back to Him. 

Third, you must ask your Heavenly Father, in the name of His Son, Jesus Christ, to manifest the truth of The Church of Jesus Christ of Latter-day Saints unto you. Ask with a sincere heart and with real intent, having faith in Christ. 

There is also a fourth step, given to us by the Savior: “If any man will do [God’s] will, he shall know of the doctrine, whether it be of God, or whether I speak of myself.” In other words, when you are trying to verify the truth of gospel principles, you must first live them. Put gospel doctrine and Church teachings to the test in your own life. Do it with real intent and enduring faith in God.
("Receiving a Testimony of Light and Truth", Dieter F. Uchtdorf, Oct 2014)

-

As community members work together unselfishly in a common cause, for the common good, they find that whatever their backgrounds, convictions, or experience, there is much more which unites them than which draws them apart. They come to understand that no group in society has a monopoly on goodness, wisdom, talent, knowledge, or energy. (“No More Strangers” Alexander B. Morrison, Ensign Sep 2000)

-

We do not have a monopoly on goodness. There are God-fearing men and women in all nations who influence for good those with whom they associate. ("You Make a Difference", Thomas S. Monson, Apr 1988)

-

No group has a monopoly on virtue or an immunity from the commandment to change. ("Repentance and Change", Dallin H. Oaks, Oct 2003)

-

our Church does not have a monopoly on good people, but we have a remarkable concentration of them. My associations in the organizations of The Church of Jesus Christ of Latter-day Saints have given me the basis to recognize, appreciate, and enlarge my associations with people of quality in other churches and organizations ("The Gospel in Our Lives", Dallin H. Oaks, Apr 2002)

-