I recalled that Thomas Merton was once a nonbeliever so I found an old copy of Seven Story Mountain to see what it was the brought about his conversion:
In section vi
I was fascinated by these Byzantine mosaics. I began to haunt the
churches where they were to be found, and, as an indirect consequence,
all the other churches that were more or less of the same period. And
thus without knowing anything about it I became a pilgrim. I was unconsciously
and unintentionally visiting all the great shrines of Rome,
and seeking out their sanctuaries with some of the eagerness and avidity
and desire of a true pilgrim, though not quite for the right reason.
And yet it was not for a wrong reason either. For these mosaics and frescoes
and all the ancient altars and thrones and sanctuaries were designed
and built for the instruction of people who were not capable of
immediately understanding anything higher.
And now for the first time in my life I began to find out something
of Who this Person was that men called Christ. It was obscure, but it
was a true knowledge of Him, in some sense, truer than I knew and
truer than I would admit. But it was in Rome that my conception of
Christ was formed. It was there I first saw Him, Whom I now serve as
my God and my King, and Who owns and rules my life.
These mosaics told me more than I had ever known of the doctrine of a God of infinite power, wisdom, and love Who had yet become Man, and revealed in His Manhood the infinity of power, wisdom and love that was His Godhead. Of course I could not grasp and believe these things explicitly. But since they were implicit in every line of the pictures I contemplated with such admiration and love, surely I grasped them implicitly-I had to, in so far as the mind of the artist reached IT1Y own mind, and spoke to it his conception and his thought. And so I could not help but catch something of the ancient craftsman’s love of Christ, the Redeemer and Judge of the World.
It was more or less natural that I should want to discover something of the meaning of the mosaics I saw-of the Lamb standing as though slain, and of the four-and-twenty elders casting down their crowns. And I had bought a Vulgate text, and was reading the New Testament.
I was in my room. It was night. The light was on. Suddenly it seemed to me that Father, who had now been dead more than a year, was there with me. The sense of his presence was as vivid and as real and as startling as if he had touched my arm or spoken to me. The whole thing passed in a flash, but in that flash, instantly, I was overwhelmed with a sudden and profound insight into the misery and corruption of my own soul, and I was pierced deeply with a light that made me realize something of the condition I was in, and I was filled with horror at what I saw, and my whole being rose up in revolt against what was within me, and my soul desired escape and liberation and freedom from all this with an intensity and an urgency unlike anything I had ever known before. And now I think for the first time in my whole life I really began to pray-praying not with my lips and with my intellect and my imagination, but praying out of the very roots of my life and of my being, and praying to the God I had never known, to reach down towards me out of His darkness and to help me to get free of the thousand terrible things that held my will in their slavery.
All we can do is be good examples and God does the rest.