The doctrine has roots in the Holiness movement's search for a definite, datable experience of entire sanctification, but Pentecostalism gave it a new shape. Charles Parham, teaching at a small Bible school in Topeka, Kansas, concluded from the book of Acts around 1900 that speaking in tongues was the biblical sign that a believer had received Spirit baptism, and one of his students, Agnes Ozman, reportedly spoke in tongues on January 1, 1901, an event Pentecostals mark as an early confirmation of the teaching.
William J. Seymour, a Black preacher who had studied briefly under Parham, carried the teaching to Los Angeles and opened revival services on Azusa Street on April 9, 1906. The meetings ran for years, drew a famously interracial crowd unusual for the period, and sent participants back out across the country and abroad, planting the doctrine of Spirit baptism with tongues as evidence at the center of dozens of new denominations that trace their founding directly to the revival.
The doctrine of initial evidence, that tongues specifically, not merely some manifestation of the Spirit, marks the moment of Spirit baptism, became the line distinguishing classical Pentecostal denominations from the broader Charismatic renewal that later carried similar experiences into Catholic, Anglican and mainline Protestant churches without requiring tongues as proof.