Some of the different Christian denominations in the U.S. during the 19th century began to produce a variety of new leaders, like Phoebe Palmer and William Boardman, who focused on what they would call "Christian Perfection." These writers did not leave their denominations, but introduced movements within them that centered on lives of holiness. Phoebe Palmer associated sanctification as a baptism of the Spirit with the onset of spiritual power that would make possible a life of holiness.
In 1870, Asa Mahan, teacher and leader of the Oberlin Holiness movement, described the "baptism of the Holy Ghost" as an act by which the Holy Spirit accomplishes sanctification for the faithful. Mahan and Charles Finney, another 19th-century revivalist, began articulating a language of the Holy Spirit that would later become the theological underpinnings of Pentecostalism's emphasis on the active work of the Holy Spirit. They taught that the Spirit imbued people with supernatural gifts intended to serve as an outward sign of inward sanctification.
Holiness revivals spread through the work of individual evangelists and writers such as Palmer and Mahan, but one of its most successful avenues for the dissemination of Holiness theology was the camp meeting. As early as 1867, these camp meetings were calling people together to "realize together a Pentecostal baptism of the Holy Ghost." Themes at these meetings, themes running throughout much of the Holiness literature of the time, made a decisive shift from traditional Methodist themes to the theme of the role of the Holy Spirit in imbuing power.
The blurring of the lines between holiness and power, the former related to issues of sanctification and the latter to signs of the Spirit, marked the permanent schism between Holiness movements and early Pentecostal stirrings in the south and midwest U.S. The ministry of Benjamin Harden Irwin, founder of the Fire-Baptized Holiness Church, began to join holiness and experience, and began equating the sanctification process with the experiential operation of the Holy Spirit. Irwin spoke of a "baptism with fire" obtainable by faith; this was a separate act from the process of sanctification that early Holiness and Methodist preachers taught. That one could be free of sin, perfected by God, did not seem to be the key point of discord any longer within the Holiness movement. The point of discord was a movement that stressed power over sin through defining physical manifestations brought on by the Holy Spirit. By the early 20th century, those who preached Pentecostal experiences, like speaking in tongues, were separating from Holiness churches, which pursued issues of sanctification.