Protestants as well as Catholics confess their belief in one church. But the two groups understand church unity differently.
According to a recent document published by the Vatican, the church of Jesus Christ is identified with the church “governed by the successor of Peter and the Bishops in communion with him”. Christian unity is conceived as a world-wide organized society under the leadership of Catholic bishops and headed by the bishop of Rome.
According to this theory, the Orthodox and Protestant churches “suffer from defects”; the latter are merely “ecclesial Communities” and not “churches in the proper sense” -- primarily because they do not submit to the headship of the Pope, the bishop of Rome.
However there is no convincing biblical evidence that Peter was appointed supreme pastor and ruler of the whole church. We know from the New Testament that Peter was considered a pillar in the early church, but he shared this reputation with two other apostles. “James, Peter and John [were] reputed to be pillars” (Galatians 2:9). Peter had no supreme authority over the other apostles or the universal church.
Nor is there historical proof that the bishop of Rome ever exercised universal jurisdiction over the catholic church. The sixth canon of the Council of Nicea indicates the very opposite:
“The ancient customs of Egypt, Libya and Pentapolis shall be maintained, according to which the bishop of Alexandria has authority over all these places since a similar custom exists with reference to the bishop of Rome. Similarly in Antioch and the other provinces the prerogatives of the churches are to be preserved.”The Council recognized the authority of the bishop of Alexandria over certain territories in North Africa, just as Rome and Antioch exercised similar power in their regions. By this time in church history, the bishops of important cities were ruling over the churches in their geographical areas. Rome’s authority, like Alexandria and Antioch, was regional and not universal.
The bishops of the Council of Nicea believed in one church, as the Nicean Creed asserts, but they did not recognize the bishop of Rome as supreme head over them.
Protestants regard the church as the spiritual body of Christ, made up of every true believer, born by the Spirit of God and redeemed by the blood of Christ. Christians are united in Christ despite the diversity and differences between individual believers and their local congregations. Since we are spiritually united, Christians are called to “make every effort to keep the unity of the Spirit through the bond of peace” (Ephesians 4:3).
We should pray and work towards the unity and peace of the church without compromising the truth of the Gospel. But we cannot accept the papal claim to universal jurisdiction. That claim is neither biblical nor historical; it is one of the greatest stumbling blocks in the way of unity.