This abstract discusses the characteristics of the true church according to Christian views, emphasizing the importance of faithfulness to the Word of God as the primary foundation. The true church is a community that faithfully proclaims the Gospel of Christ purely, without addition or subtraction from the teachings of the Bible. This faithfulness serves as the basis for the church’s existence as the living body of Christ, functioning to spread salvation to all people. Besides faithfulness to the Word, the proper administration of the sacraments is also an important characteristic of the true church. Sacraments such as baptism and the Lord’s Supper are conducted according to Christ’s commands and serve as means of grace that strengthen the faith of the congregation. The spiritual discipline practiced within the church maintains the holiness of the members and encourages repentance and restoration, so that the community continues to live in truth and love. Unity and holiness reflect the church’s calling to live in love and truth, while the apostolic nature shows its adherence to the teachings of the apostles. Catholicity affirms that the true church is universal and transcends cultural and geographical boundaries.

The Protestant Reformation, initiated by Martin Luther in the 16th century, was a pivotal event in Christian history that shook the structure of the Catholic Church and had a profound impact on many aspects of life. This movement arose from dissatisfaction with church practices believed to be in conflict with Biblical teachings, such as the sale of indulgences. Through his 95 Theses, Luther emphasized that salvation could only be achieved through faith (sola fide) and that the Bible was the sole source of authority (sola scriptura). These teachings led to a split between the Catholic Church and Protestantism, sparking a broader theological reformation across Europe. Beyond its theological influence, the Protestant Reformation also brought about significant social, political, and cultural changes. Luther's teachings on the importance of education and literacy encouraged the translation of the Bible into local languages, allowing the faithful to access the Scriptures directly. The Reformation also introduced the concept of religious freedom and reshaped the relationship between church and state, with several countries adopting Protestantism as their official religion. Overall, the Protestant Reformation not only transformed the church's structure but also had a major impact on the development of Western social and political systems, creating new concepts of individual freedom and religious authority.