Sundar Singh was born in 1889 in Punjab to a Sikh family. Following a conversion experience in which he encountered the risen Christ, he became a Christian, a decision that led to his rejection by family and community. Rather than adopting Western ecclesiastical forms, Singh made the radical decision to become a Christian sadhu—adopting the saffron robes, ascetic practices, and wandering lifestyle of Hindu holy men—as a means of making Christ accessible to Indian seekers. For decades, he traveled throughout India, Tibet, Central Asia, and beyond, preaching Christ through parables, spiritual teaching, and personal witness. His life exemplified a form of radical inculturation, demonstrating that one could follow Christ while honoring and utilizing the spiritual frameworks of one's own culture. Singh's legacy consists of devotional writings and accounts of his spiritual experiences, though the authenticity of some attributed texts remains disputed. Around 1929, while attempting to evangelize Tibet, he disappeared in the Himalayan mountains under circumstances that remain unclear. He is presumed to have died around that time, though some accounts suggest he may have continued his ministry in secret. His life and witness continue to inspire Christians concerned with cultural sensitivity, mystical spirituality, and the contextualization of the gospel.

Sundar Singh exemplifies the principle of inculturation—the conviction that Christian faith can be authentically expressed within non-Western cultural and spiritual forms. He is honored by missiologists, contextual theologians, and those concerned with Christian-Hindu and Christian-Buddhist dialogue. His sadhu lifestyle anticipates later concerns with the indigenization of Christianity in Asia. He is venerated as a faithful witness to Christ who refused the false choice between Christian faith and cultural identity. The mystical and apophatic dimensions of his spirituality appeal to contemporary seekers of contemplative Christianity.