Insights from Elder Jeffrey R. Holland of the Quorum of the Twelve Apostles:
Behold, how good and how pleasant it is for brethren to dwell together in unity! Psalm 133:1
Our bodies, our souls and our psyches were meant to be at peace. We all know the illness of the physical body when some element of our health is out of order, when some process is not in unity with all the others. It is even more wrenching when that happens in the mind or in the spirit.
For example, real illness can come from the guilt that accompanies going against the unity of our beliefs, against the integrity of our moral commitments. We have all seen examples where there has been a lack of unity in marriage, or in a family, or in an athletic team, or in the community at large.
Paul taught that a body—whether the body be an individual or a church or a nation—cannot war against itself, cannot be antagonistic one part to another, cannot survive with one element saying that it has no need of another.
see 190: (1 Corinthians 12:12-17) Life is happier at every level if we are unified and harmonious, always allowing for differences of opinion and individual personalities, but never letting legitimate distinctions and uniqueness bring pain and strife so serious that it compromises the health of the person.
God expects us to be unified as His children and as His Church. He expects us to “dwell together” in unity.” (Moses 7:18) In His magnificent Intercessory prayer Christ pled for that unity in the lives of His disciples. (John 7:18)
Later the New Testament saints did believe and were of one heart and one mind.” (Acts 4:32)
We are, as members of the Church, the body of Christ. He expects unity of purpose and sublimation of selfishness when the health of the whole body is at stake. This helps the entire enterprise—as well as the individuals in it—to fend off difficult times or triumph over them when they come. Truly if we are not one in the family of God, we are not His. ~Elder Jeffrey R. Holland, For Times of Trouble p.143