Tolkien deliberately left most of his Middle-earth cultures without any form of organized religion. However, the Dúnedain culture, which descends from Númenorean and Edain culture, is exceptional in this regard, characterized as monotheists with a religion dedicated to Eru Ilúvatar and marked, through both cultural and narrative similarities, as sharing a special relationship with him that echoes the covenantal relationship of Biblical Israel with God. These parallels are particularly visible in shared motifs of the Akallabêth and Exodus, the invocation of Ilúvatar in oaths, the Númenorean pilgrimage festivals, and the designation of the Meneltarma and Halifirien as sacred mountains in the order of Sinai and Zion.
Cooper, Caryn L. and Whetter, Kevin S.
"Hear, O Númenor!: The Covenantal Relationship of the Dúnedain with Ilúvatar,"
Journal of Tolkien Research: Vol. 11
, Article 6.
Available at: https://scholar.valpo.edu/journaloftolkienresearch/vol11/iss2/6