A three-year (1948–1951) teaching experience at St. Xavier's Collegiate School, Calcutta, made him discover the way Hinduism shaped the personalities of the students entrusted to him.

This discovery about the variety of religions was the beginning of a lifelong search: "does God's self-revelation necessarily pass for all through the person of Jesus Christ?

"[1] After being ordained priest in Kurseong, India he completed a doctorate at the Gregorian University in Rome on the religious anthropology of Origen of Alexandria.

Besides numerous articles on theological and inter-religious topics, he published in 1973 (with Josef Neuner) a collection of church documents, The Christian Faith, that went into seven editions over twenty years.

His book Jésus-Christ à la rencontre des religions (1989) was well-received and promptly translated in Italian, English and Spanish.

As the son of God incarnate, Jesus is the center of history and the key to the entire procession of salvation, and his resurrection confers universal significance on his human existence.