When people think of the early Christians, they often picture doomed individuals thrown onto the floor of the Colosseum to face starving lions. Or they may think of small congregations huddled in dark underground catacombs. While such popular depictions are certainly based in historical facts, the mental images they conjure often leave out the most important message those first Christians wished to communicate: their indomitable hope.

This virtue, given to them in baptism along with faith and charity, also gave them their primary reason for living. They believed they had God’s own life within them, enabling them to live in an unwelcoming world — and die in it — with bold confidence. For their hope was not for fulfillment in this life. It was for eternal happiness in the next.

They would often say “Maranatha” in their prayers and liturgies: Come, Lord Jesus. Their conviction about the afterlife and the power of Christ’s resurrection gave them extraordinary courage.

A common characteristic of the ancient world was a kind of depression of the spirit. Many people lacked hope. What could new things or experiences matter if human existence had no apparent meaning or larger purpose? A Latin epitaph from those days reads “De nihilo ad nihil quam cito recedimus” — How quickly we fall back from nothing to nothing. With nothing true and transcendent to live for, people filled their lives with games and other pastimes, many of them violent. But, in the end, these things couldn’t fill the human heart. In fact, they only left it feeling more bitter and empty.

Pagan religions attempted to fill that emptiness. People in the first three centuries had some belief in gods and goddesses, but the elaborate mythologies that sprang up to support them were obvious projections of human wants, fears and frustrations. Eastern myths based on nature and the seasons spoke of new life, but they were either ambiguous or self-contradictory. None of them really asked a person to change his attitude or behavior from within. None gave a compelling reason for living each day.

Meanwhile, the followers of Christ believed that everything, even pain and suffering, brimmed with meaning. Their happiness derived not from their earthly circumstances, but from their trust in Christ — which held fast regardless of their circumstances. Instead of mysterious nature rituals, instead of complicated Gnostic formulas of salvation, these men and women had a source of hope that came from Christ’s Church and from receiving the Eucharist, God’s own body and blood. The early Christians lived these mysteries as the most important reality of their lives. Little by little, as the years went by, they transformed ancient society.

Fast-forward to our world. Many people today worship “gods and goddesses” of various kinds. Some revere the gods of science and technology, others the god of progress (whatever that means), others the goddess of hedonism. There are many ideologies and religions that worship nature, including the goddess Earth with all of her adherents. Some place their trust in political correctness, while others simply adopt a cool indifference to mankind and his suffering — a sort of neo-Stoicism. Some respect and celebrate human virtue, as the Stoics did, but only for the sake of pride or self-satisfaction.

None of these ideologies can truly bring hope to the world. This was the main thesis of Pope Benedict’s 2007 encyclical, Spe Salvi (Saved in Hope). After delineating some of the lesser hopes people live by in our day, the Holy Father concludes that our only true hope is God, “who encompasses the whole of reality and who can bestow upon us what we, by ourselves, cannot attain. The fact that [hope] comes to us as a gift is actually part of hope. God is the foundation of hope: not any god, but the God who has a human face and who has loved us to the end, each one of us and humanity in its entirety.”

Because of their supernatural hope, early Christians endured all kinds of persecutions, though some of them fell away through human weakness. They believed in the marriage bond, which they held to be indissoluble, based on Christ’s own words. This was almost like an affront in a world where many Roman men had their mistresses and their wives had secret lovers. They would not practice contraception in their marital relations, but were open to children, since they valued every child as a gift from God, destined to be part of Christ’s eternal Kingdom. Procured abortion was an unspeakable crime in their sight, since it was an offense against the life-giving God they believed in. Their love for children went so far that they even went to the street corners of the big Greco-Roman cities where pagan couples would leave their unwanted children, then adopted these boys and girls into their own homes. Where many non-Christians or Gnostic heretics rejected marriage and the family, the Christians exalted it.

There were also many men and women throughout the Roman Empire who gave themselves completely to Christ in celibacy, as a way of imitating Christ himself and spreading his Kingdom on earth. There were not only priests who made this commitment, but also ordinary lay faithful. This extraordinary example of faith and hope astounded the pagan world, as it continues to astound people today. That young men and women would give up their right to sex and marriage for the sake of a higher love was, at least for some, a witness almost as strong as martyrdom.

The hope of the early Christians had two factors that almost seem in tension: They dearly longed for the Parousia, Christ’s coming with his everlasting Kingdom — but, at the same time, they looked at the world as something to be loved and redeemed now. The earliest Christians did not separate themselves from the world, but remained within it, trying to sanctify it.

All of these factors had a transforming effect on ancient society. Little by little the “mustard seed” grew, as in the Gospel parable. Christians began as a small and despised group of individuals and families in a pagan world, but eventually converted that world to Christ. How did they do it? One heart at a time.

“To be truly alive is to be transformed from within, open to the energy of God’s love,” Pope Benedict told the throngs of young people at World Youth Day in Australia last year. “In accepting the power of the Holy Spirit, you can also transform your families, communities and nations.”

To transform something is not to destroy it or alter it in a radical way. It is to change something from within, giving it a new form of life or state of existence. That is what the early Christians did for their society. It is what we Christians must do for ours.

Opus Dei Father Michael E. Giesler is the author of Grain of Wheat (Scepter, 2008) and two other works of historical fiction.