When Christianity is seen as an exclusive and singularly privileged religion by its adherents, history demonstrates that it does well. In fact, one can argue from history that to the extent Christians professed their faith in Christ as being wholly unique- not only a faith unlike others but a corresponding morality unlike others –conversions were never wanting. This defies conventional wisdom, to be sure. But the truth is that with high standards Christianity grew by leaps and bounds even when state-sponsored persecutions were unleashed by the Roman Empire.
Fr. Raoul Plus, in his book, Radiating Christ, S.J. captured the genius of having high spiritual and moral standards. He wrote the following in 1944:
“There is no need to be afraid of asking too much. What attracts the young especially is the hard task, the difficult exploit. If you want volunteers for easy work, they are not enthusiastic. When faced with a choice of a religious order, souls that have a vocation seem by instinct to adopt those orders which are more fervent and more exacting. Similarly, souls will only enroll themselves in the service of a leader or an organization if they see that there are sacrifices to make and hard work to do.”
Our Lord capitalized on the attractiveness of such an appeal when he demanded from his disciples their very lives. He wanted everything from them! To bury a deceased loved one or to even say farewell to one’s family had to give way to following him. And this, more than anything else, was symbolic of the kind of conversion he required from his followers. In the Gospel of Mark he prefaced the kerygma with these revolutionary words: "This is the time of fulfillment. The kingdom of God is at hand. Repent, and believe in the gospel." (Mark 1:15)
To “repent and believe” hardly seems revolutionary. But it was to the ancient pagans! To believe all that Christ taught without exception; to observe his moral law as a condition of being his disciple; and to be exclusively devoted to him while manifestly rejecting the gods of the Greco-Roman world [also known as Hellenism] was preposterous to ancient pagan sensibilities.
Michael Green made this very point in his book, Evangelism in the Early Church (1970, 2003). He argued that Christian conversion- especially as it pertained to belief, morality and the exclusive claims that Christianity made on its adherents -was not only a scandal, but it was an enigma to the ancients. It simply was unknown to the unbaptized world.
As for belief, Green said, “In the first place, Hellenistic men and women did not regard belief as necessary for the cult.” “So long as the traditional sacrifices were offered,” Green continues, “so long as the show went on, all would be well. You were not required to believe in the deities you worshiped: many people like Lucretius and Juvenal scoffed at the stories of the traditional gods but they were careful to continue the sacrifices on which on which the safety of the state and the well-being of society were held to depend.”
Keep in mind that intolerance to religious error is a Judeo-Christian thing. The ancient pagans, on the other hand, did not subscribe to a creedal religion. The worship of certain gods was rarely fixed and religious tolerance was a social necessity. Hence, to be selective as to what one believed about the gods was entirely consistent with being a “good pagan.”
But Christianity was different. It inherited an imperative for doctrinal purity from Judaism. Christ said to his Apostles to make disciples of all nations by “teaching them to observe all that I have commanded you.” About four centuries later, St. Augustine, as with the early Christians, took our Lord’s words, “all that I have commanded” quite seriously. He said, "There can be nothing more dangerous than those heretics who admit nearly the whole cycle of doctrine, and yet by one word, as with a drop of poison, infect the real and simple faith taught by our Lord and handed down by Apostolic tradition." Therefore, it is no exaggeration to say that there was an expectation in the early Church that all of what Christ commanded was to be believed and obeyed.
“Secondly," Green adds, "Hellenistic men and women did not regard ethics as part of religion. It made little difference to your behavior whether you were a devotee of Mithras or a worshiper of Isis.” That’s right. Being a priest or priestess in ancient Greece did not necessitate high moral standards. Even the Greek philosophers were wanting in virtue. As regards to Plato, he “condemned drunkenness but approved of it on the feast of Bacchus. In the ‘Republic’ he recommends infanticide and a community of wives.” (James Cardinal Gibbons, Our Christian Heritage 1889)
It is a Christian invention that religion and morality go hand in hand. Even the charge of hypocrisy that is often leveled against the Church nowadays is only possible because it was the Church herself that made belief and morality to be inseparable. Thanks to her, the creed that one professes is expected to correspond to the morality one lives. And all who wanted to join her ranks during those first centuries had to make a clean break with their immoral past and embrace a life of virtue. No half measures, partial commitments or nominal Christians were countenanced. “For whoever keeps the whole law,” wrote St. James, “but falls short in one particular, has become guilty in respect to all of it.” (2:10) Fidelity to all of God's laws gives credibility faith. Morality and faith cannot be divorced. Indeed, this is yet another reason why conversion was an enigma to the ancient pagans.
“The third reason why the idea of Christian conversion was so surprising to Hellenistic people,’ Green writes, “was the exclusive claims it made on its devotees. Christians were expected to belong, body and soul, to Jesus, who was called their master…” It’s not just Michael Green that makes this important point. E. Glenn Hinson, in his book, The Evangelization of the Roman Empire: Identity and Adaptability (1981) also brings to the fore this idea of exclusivity. Hinson said, “What was built into their corporate life was the exclusivism of the monotheistic covenant…The institutional forms, developed gradually in response to the challenge of enlisting and incorporating new converts, did much to inculcate and sustain the exclusivism of Christianity.”
This Christian exclusivity was expressed in ancient liturgical prayer known as the Gloria. The Gloria was added to the Mass during the second century; not too long after St. John the Apostle died. The prayer ends with the following exclamation: “For you alone are the Holy One, you alone are the Lord, you alone are the Most High, Jesus Christ, with the Holy Spirit, in the glory of God the Father. Amen.” If one were to read between the lines it might read something like this: glory only to the Holy Trinity and to no other gods! But to refuse worship or even honor of other gods was considered to be the height of arrogance and intolerance. Yet, the early Church flourished in spite of it; even in a highly pluralistic civilization.