“Religion guides all the processes in our lives, without us even knowing it,” the Estonian composer Arvo Pärt said in a recent phone interview. “It is true that religion has a very important role in my composition, but how it really works, I am not able to describe.”

Mr. Pärt, 78, is a practicing Eastern Orthodox Christian, which is frequently mentioned but often left unexplored. Critics and fans compare his contemplative, austere music to the painted icons central to Eastern Orthodoxy, but rarely delve into those connections in great detail…

“There’s this kind of universally accessible spirituality going on, and yet it evidently has some particular sources in the context that he locates his own prayer life,” said Peter Bouteneff, a professor of theology at St. Vladimir’s Orthodox Theological Seminary in Yonkers. “It’s where he goes to church, it’s the texts that he reads, the ancient Greek fathers,” he added. “This is what feeds his soul, and therefore: Is there some connection between this universally perceived and universally accessible spirituality, and the particular foundations in Eastern Orthodoxy?”

It is a question that Mr. Pärt is not quite comfortable answering, though he will receive an honorary doctorate from the seminary. When asked about the religious content of his music, he responded: “I am actually writing music for myself, based on my own cognition. Because of that, it reflects values that are important to me.”

“If the listener also perceives what I felt while composing, I am very happy about it,” he added. “I am not taking the task in my music to discuss some religious or special Orthodox values. I am trying to reflect the values in my music that could touch every individual, every person.”

Mr. Pärt’s fervor did not always work in his favor. He first made waves in the Estonian compositional world for “Nekrolog,” an orchestral work critiqued by Soviet censors for its 12-tone language. The 1968 premiere of “Credo,” his first overtly sacred piece, drew further negative attention. This time, it was not the music but the title that irritated the authorities: The religious message was interpreted as an act of political dissidence. (The music theorist Yuri Kholopov once remarked that “God and Jesus Christ were bigger enemies to the Soviet regime than Boulez or Webern.”)

Mr. Pärt was unofficially censured, his music disappearing from concert halls. In a radio interview the year of the “Credo” premiere, he attempted to voice his beliefs publicly. Questioned about his main influences, Mr. Pärt responded: “Of course, Christ. Because he solved his fraction perfectly, godly.” The section was edited out of the broadcast version, to avoid a government ban.

Following the “Credo” controversy, Mr. Pärt fell mostly silent. He converted to Orthodox Christianity in 1972 upon marrying his second wife, Nora. When he re-emerged in 1976, it was with the crystalline stillness of “Für Alina,” the first composition shaped by his tintinnabuli technique: a weaving-together of melodic lines in which one voice outlines a chord while the other circles around it.