The people who heard Jesus's disciples proclaiming the Good News were as impressed by what they saw as by what they heard. They saw lives that had been transformed — men and women who were ordinary in every way except for the fact that they seemed to have found the secret of living. They evinced a tranquility, simplicity, and cheerfulness that their hearers had nowhere else encountered. Here were people who seemed to be making a success of the enterprise everyone would like to succeed at — life itself.
Specifically, there seemed to be two qualities in which their lives abounded. The first of these was mutual regard. One of the earliest observations by an outsider about Christians that we have is, "See how these Christians love one another." Integral to this mutual regard was a total absence of social barriers; it was a discipleship of equals. Here were men and women who not only said that everyone was equal in the sight of God but who lived as though they meant it. The conventional barriers of race, gender, and status meant nothing to them, for in Christ there was neither Jew nor Gentile, male nor female, slave nor free. As a consequence, in spite of differences in function or social position, their fellowship was marked by a sense of genuine equality.
Their second distinctive quality was happiness. When Jesus was in danger, his disciples were alarmed; but otherwise it was impossible to be sad in Jesus's company. And when he told his disciples that he wanted his joy to be in them, "that your joy may be complete," to a remarkable degree that objective was realized.
Outsiders found this baffling. These scattered Christians were not numerous. They were not wealthy or powerful, and they were in constant danger of being killed. Yet they had laid hold of an inner peace that found expression in a joy that was uncontainable. Perhaps "radiant" would be a better word. "Radiance" is hardly a word used to characterize the average religious life, but no other word fits as well the life of these early Christians.
— Huston Smith, The Soul of Christianity