Mosiah 25

21  Therefore they did assemble themselves together in different bodies, being called churches; every church having their priests and their teachers, and every priest preaching the word according as it was delivered to him by the mouth of Alma.
22  And thus, notwithstanding there being many churches they were all one church, yea, even the church of God; for there was nothing preached in all the churches except it were repentance and faith in God.

Janet and I were at General Conference in Salt Lake City two weeks ago. Standing in the lobby of the conference center, I could hear various languages. We were near a fountain and there were 3 ladies in beautiful African native dresses. Reading about the people of King Mosiah, I notice that they were united in one faith and one church. They were descendants of Nephi, Mulek, and Laman. Despite the different backgrounds, they came together because of their common faith in Jesus Christ. 

I have attended church in various countries, including Japan, Peru, Germany, Switzerland, Lebanon, and Mexico. The ward I attended in Tokyo was a wonderful example of the ability of a common doctrine and faith in Jesus Christ and the restored gospel to bring together people from many nations. We were from the United States, Japan, Australia, Italy, Indonesia, India, Great Britain, and other nations. We shared no common culture, but we shared a common faith. Our ward in Houston has members from as many as 35 different nations. I hometeach a sister from Venezuela. An Iranian sister teaches in the Primary nursery. One of Janet's counselors is from Nigeria. A member of the elders quorum presidency is from Peru. The differences in culture and nationality don't matter at all. We are one in the faith. 

Paul wrote to the church in Ephesus and plead for unity in this way (chapter 4):

1  I THEREFORE, the prisoner of the Lord, beseech you that ye walk worthy of the vocation wherewith ye are called,

2  With all lowliness and meekness, with longsuffering, forbearing one another in love;

3  Endeavouring to keep the unity of the Spirit in the bond of peace.

4  There is one body, and one Spirit, even as ye are called in one hope of your calling;

5  One Lord, one faith, one baptism,

6  One God and Father of all, who is above all, and through all, and in you all.

One Lord, one faith, one baptism. We are all children of one Father in Heaven.