David Shelby Corlett preaches on the connection between heart purity and the baptism with the Holy Spirit, emphasizing that true evidence of this baptism is the purification of the heart by faith. He highlights how the Holy Spirit guards against counterfeits, showing that speaking in tongues is not the ultimate evidence, but rather the purity of the heart. Corlett explains that heart purity, synonymous with entire sanctification, is achieved through the filling of the Holy Spirit, who dispels all that is carnal and fleshly, bringing unity and a central desire to do God's will.

It was stated in the promise made by John the Baptist concerning this baptism with the Spirit that it would include a thorough purging of the threshing floor, the wheat would be garnered, the chaff destroyed. The "tongues like as of fire" appearing upon each of them on the day of Pentecost was the symbol of an inner cleansing. The testimony of Peter concerning the genuineness of the work done at the house of Cornelius where the Gentiles first received the Baptism with the Holy Spirit was based upon the consciousness that their hearts were purified. "And God, which knoweth the hearts, bare them witness, giving them the Holy Ghost, even as he did unto us; and put no difference between us and them, purifying their hearts by faith" (Acts 15:8, 9). The result of the baptism of the Spirit, according to the testimony of this leader of the disciples, was heart purity. Let us digress here sufficiently to note that this heart purity was the evidence to Peter that the work done at Cornelius' house was genuine. These Gentile believers "spake with tongues," so did the disciples at Pentecost. But speaking with tongues was not the evidence to Peter, it was heart purity. Note how carefully the Holy Spirit guards the evidence of His fullness from being counterfeited. Even the most honest "tongues follower" today will admit that tongues may be counterfeited. If speaking with tongues is the evidence of the baptism with the Holy Spirit, how would anyone know whether his tongues were the genuine or the counterfeit? There could be no absolute way to tell. But it is clear that speaking with tongues is not the evidence. Something far more assuring and more greatly needed is the evidence, that is, heart purity. There can be no counterfeit to heart purity. One cannot purify his own heart, the devil cannot purify the heart; only God can do it. He has so jealously guarded the evidence of the 'baptism with the Spirit that there can be no counterfeit. He purifies the heart by faith. This assures us that heart purity, or entire sanctification, and the baptism with the Holy Spirit are one and the same experience. But let us note this heart purity. Why is it pure? Because the Holy Spirit fills it. This third per son of the Trinity is not called "holy" because He is more holy than the other two members of the Trinity; He is called the Holy Spirit because it is His work to make God's children holy. He fills the whole heart, the whole life. By His fullness He dispels the carnal and the fleshly, just as light dispels the darkness. The inner conflict is gone because the temple is fully occupied by the one ruler. The heart is pure because the source of all purity -- the Holy Spirit -- fills it. It is a life with a unity of purpose, an integration of all the various phases of life around one central desire -- the doing of the will of God. The consciousness of His presence fills the heart and mind, it is pure. He abides in His fullness and He keeps it pure.