Then Jesus said to those Jews who believed Him, “If you abide in My word, you are My disciples indeed. And you shall know the truth, and the truth shall make you free.” (John 8:31,32).
Of central importance is TRUTH. Of lesser importance is the ANTIQUITY of an institution. Indeed, from the Roman Catholic perspective, the problem with Protestants is not so much that they branched off the Catholic Church in the sixteenth century (after all the branch is still organically connected to the roots). The principal allegation against the Protestants is that they have excluded certain apostolic beliefs and included novel non-apostolic ones.
From the Protestant perspective, the reformation was a process of removing certain human traditions that had been introduced in the post-apostolic church, and restoring to prominence those truths that had been ignored, such as the centrality of Scripture and salvation by grace through faith.
On the other hand, Rome cannot justify her position by an appeal to its antiquity. Like the Protestants, Rome must prove that her doctrines are apostolic. There is always a tendency for decadence in any church or organization. Since it is older, there was more time for weeds of human traditions to grow around the church of Rome and choke the truth.
The Roman church is old, but older still is Judaism. Yet Judaism is a false religion. There was a time when the Jews were God's people, but since they twisted the message of the Scriptures by their traditions, and rejected the promised Messiah, they have been set aside. However, God always had a remnant according to the election of grace among the apostate nation. They believe. They are part of the true Israel of God. It must be the same among professing Christians in the New Testament era.
I open the history books to search for the virgin bride of Christ. I am dismayed when I read how many professing Christians denied the Deity of the Lord Jesus during the Arian controversy. I am amazed to find the seeds of damnable heresies already present in the apostolic and early church. As early as the second century some Christians had departed from the Gospel and embraced false doctrines such as purgatory. Later on, others approved of the making and bowing down before graven images, contrary to the commandment of God. I am troubled when I read about the Donatists in North Africa who were persecuted by the Catholics, not because of some heresy but simply because they upheld a different standard about church government. The church was given the Word, the Sword of the Spirit, to extend Christ's kingdom on earth. Yet the church laid aside her spiritual weapons, and took up the sword to kill and slaughter the Muslims in a series of bloody crusades to regain the holy land. I weep when I read about the deep ignorance of the Word of God among God's people and the superstition that enslaved them. I look for holiness in the lives of the leaders but instead, there is often filth, corruption and shame. I look for the church preaching the Gospel and persuading man, but instead, I read about the tortures of the Spanish and Roman Inquisition.
Yet even in those darkest moments, God sent precious rays of light - godly people like Waldo, Savonarola, Wycliffe and Huss. In the driest deserts, there are oases of freshwater and life. There were always true, genuine Christians, both within the Catholic churches of the East and the West, and outside, such as the Waldenses. For Christ promised that he would build his Church and the gates of hell will never prevail against it.
God has not cast away His people whom He foreknew. Or do you not know what the Scripture says of Elijah, how he pleads with God against Israel, saying, “LORD, they have killed Your prophets and torn down Your altars, and I alone am left, and they seek my life”? But what does the divine response say to him? “I have reserved for Myself seven thousand men who have not bowed the knee to Baal.” Even so then, at this present time, there is a remnant according to the election of grace (Romans 11:2-5).
There are genuine Christians and genuine churches today as well. They are recognized by their obedience to the truth of the Gospel.