The Purpose of the Church
When we trust in Christ and become saved, God does not just call us home. He has left us His church here on earth for the remainder of our lives for a purpose. This purpose of the church is evangelism. Every major Christian denomination agrees on this:
Baptists have been one the most active denominations in mission work. Evangelism is one of the core Baptist distinctives, and this has borne out in practice. Baptist missionary William Carey is known as the "father of modern missions." Today, there are tens of thousands of Baptist missionaries fulfilling the great commission.
The mission of the [National Baptist Convention] is to fulfill the Great Commission of Jesus Christ through preaching, teaching, and healing.
In fact, Baptists are the largest component of Christians who identify as "Evangelicals". While essentially every church believes in evangelism, Baptists claim the purpose as their name more than any other.
Catholics have historically been active in mission work as well. Most historically Christian countries were initially Christianized by the mission work of the Catholic Church. While the Catholic Church since the Second Vatican Council has declared that seeking social justice is "a constitutive dimension of the preaching of the Gospel" which it has been emphasizing more than literal preaching of the written Gospel, Catholics still do continue spreading the good news as well.
The first thing the Church should be doing here and now is proclaiming the Gospel.
—Agreed Statement on the Purpose of the Church by the United States Conference of Catholic Bishops
The Orthodox Church is admittedly less active in evangelism, but it still has a strong belief in it as the primary goal of the church. Orthodox missionaries have been active since the early church. With the rise of communism and its persecution of religion, the Orthodox Church more just aimed to survive. However, mission activity has been resuming since the fall of the Soviet Union, and the Greek Orthodox Church of Alexandria has still been very active in mission work in Africa.
The purpose of the Orthodox Church is to bring about the salvation of every human person, uniting each of them to Christ in the Church, transforming them in holiness, and giving them eternal life.