Both pentecostalism and the Wesleyan holiness people share the common heritage of a second work of grace linked with the "baptism of the Holy Spirit" they differed on the evidence of this second work. Pentecostalism pointed to tongues as the evidence, holiness folk pointed to entire sanctification as the evidence. As in, "Be of sin the
double cure, save from wrath and make me pure." Some pentecostal-holiness folk pointed to both as evidence.
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Modern charismatics embrace the importance of the experience of tongues without an insistance upon the historic pentecostal doctrinal foundations. Thus charismatics iinclude people from diverse doctrinal backgrounds whereas pentecostals emphasize separation from doctrinal error.
There was a split between the Pentacostals and at least one of the holiness churches over tongues..up untill then they were one!