Pentecostals say that the Spirit resides in those who are sinless

"The Pentecostals say that 'You can receive the Holy Spirit, but not with sin in your heart.' Also, 'The Holy Spirit and sin cannot abide in the same heart.' This presupposes sinlessness. 'Pentecostalism . . . makes the mastery of . . . sin to be the condition for the grace of the Holy Spirit. Grace itself, or the forgiveness of sin, appears in Pentecostalism to play a role only in the Christian's conversion, rarely appears in other discussions, and thus ceases for all practical purposes to be the center and determinate of the whole Christian life. The reversal of the apostolic sequence of grace-then-obedience lies at the bottom of the Pentecostal error' (p. 233).
The smaller print on the same page is devastating. Bruner quotes, 'Many believers count on the 'Christ for us,' but not on the 'Christ in us' [Colossians 1:27]; and yet it is this 'Christ in us' who is the hope of glory. That means: the heavenly resurrection life can only be imparted to us when we let Christ live in us. The forgiveness of sins, as important and necessary as it is, does not suffice for this.' Then Bruner notes that 'in Col. 1:27 the not primarily individual or internal, but communal congregational. . . . Furthermore 'Christ in us' is not a higher better form of 'Christ for us.' 'Is Christ divided?''
When the Pentecostals say, 'As sinners we accept Christ, as saints we accept the Holy Spirit,' Bruner answers, 'Not only is the separation of the Spirit from Christ serious (is Christ without the Spirit?) but it is suggested that while sinners can accept Christ, the Holy Spirit must be obtained by men more highly qualified. The Pentecostal conditions define the meaning of 'saints'" (P. 235). - Gordon H. Clark, The Holy Spirit, Pg. 94

Irrationalism crept into the pentecostals camp which in turn crept back into Rome

"By the end of [... World War 1] fundamentalism had moved from its scholarly form as defended by eminent theologians in the famous The Fundamentals and had become a very non-scholarly movement making progress among the less affluent population. My father was certainly among the less affluent population, as were his people; but there was only one member who took up with the new movement. That the Pentecostals accepted the five points of the original fundamentals, namely, the inerrancy of Scripture, the virgin birth, Jesus' miracles, his vicarious atonement and resurrection, admits of no doubt.
But let us remember that the Galatian Judaizers, whom Paul so vigoriously condemned, believed these five points too. What they did not believe was justification by faith alone. Did the early Pentecostals believe it? Do they believe and teach it now? Or is their developed view of tongues inconsistent with the evangelicals' historic position? However it may have been in the 1920's, more recently, beginning at the University of Notre Dame, the Pentecostals have penetrated Romanism and have welcomed numerous Catholics, if not into their assembly halls, certainly into their spiritual fellowship." - Gordon H. Clark, The Holy Spirit, Pg. 84