The Holy Trinity is the foundation of the Roman Catholic Church, and Christianity the world around. There is not a single page of the bible that does not extol the virtues and greatness of the Holy Spirit, God the Father,
Father, Son, and Holy Spirit and at the same time acknowledges the distinctive properties of each. In praising one of the three aspects of God, you are praising the three. Understanding the unity of the Trinity is helpful in understanding the unity of the Church. The Catechism of the Catholic Church details this unity in a way that is both succinct and easily understood:
The Church is one because of her source: "the highest exemplar and source of this mystery is the unity, in the Trinity of Persons, of one God, the Father and the Son in the Holy Spirit." The Church is one because of her founder: for "the Word made flesh, the prince of peace, reconciled all men to God by the cross, . . . restoring the unity of all in one people and one body." The Church is one because of her "soul": "It is the Holy Spirit, dwelling in those who believe and pervading and ruling over the entire Church, who brings about that wonderful communion of the faithful and joins them together so intimately in Christ that he is the principle of the Church's unity." Unity is of the essence of the Church (Catechism Catholic Church 813).
Just as the different aspect of the Trinity serve their own distinct purposes, so do the separate congregations and individuals who make up those congregations unify to make the whole of the Catholic Church. Though each person may bring their own individual charisms to the table, and each nation brings it's own specific traditions and idiosyncrasies they all serve the same purpose. They unite as the Church in service to the Father, Son, and Holy Spirit. We serve God the Father as a communion of His people, for it is He that has gathered us together and baptized us in His name. We are People of God. As one, we form the Body of Christ. Jesus is our head and we are His body. As the Head all actions are driven by Him. We are able to fulfill these roles because at we are Temples of the Holy Spirit. Through the Holy Spirit we are moved by, and bound to God the Father, and Jesus Christ.
There are, however, deep wounds to this unity. An organization as large and varied as the Church is just as susceptible to dissidence as any two people would be; in fact, more so. Even the most well mannered and amicable people will find themselves at odds over the most petty of things over a period of time. Why then would a group of people, such as the Church, contemplating such weighty issues, such as the salvation of our eternal souls and the correct way to worship God the Father Almighty, be any different. Whether or not these divergences are avoidable or not, they happen. Unfortunately, these conflicts have fractured the unity of the Church, and wounded her for the time being. Threats to the Church's unity appeared almost instantaneously upon her inception. Were it not for these wounds, the ecumenical councils may not have been necessary at all. While the first seven ecumenical councils could be said to be dealing with minor wounds, it was the eight council that dealt the most critical blow; culminating in the Great Western Schism. Then again in the 16th century the Protestant Reformation wounded the Church even more. These divisions, along with the discordance amongst the current leaders of the Church, have caused great harm to the unity of the Church. Attempts to quell the bleeding still continue in hopes of once again making the Church whole.