In the Name of the Father and of the +Son and of the Holy Spirit. Amen.
The Feast of the Pentecost is about Holiness, specifically where Holiness may be found.
Holiness was a circumstance fashioned by God in His creative work; where He declared it is Very Good. Holiness was a circumstance lost by Adam’s noncompliance. For most of Human History from father Abraham on through the Children of Israel; Holiness was, as it were, a divine bridgehead into the profane world, the place where heaven and earth overlapped. Holiness was a circumstance reestablished when God’s presence filled the tabernacle among the freed Israelite slaves. Its opposite pole was the state of impurity which was utterly incompatible with holiness, like light with darkness. In fact, holiness annihilated impurity, like fire which burns up gasoline.

The human world lay suspended between these two poles and within the magnetic field of either power. Everything natural and normal in it was common. Anything common could be either clean and normal, or else unclean and abnormal. Ordinary food could be common and clean, if free from impurity, or else common and unclean, if infected by impurity. If something common became holy, it ceased to be common, since it then belonged to God and existed in his domain. Likewise, if something clean became unclean, it remained common but ceased to be clean. Holiness and impurity were therefore powers which vied for the control of the world and what was in it.

Because nothing that God had created was either inherently holy or unclean, there were various degrees of holiness and impurity. The closer something came to God, the holier it became. Hence the high priest was holier than the ordinary Israelite and the holy of holies than the holy place. The ark, the altar of incense, the lamp stand, the showtable, the main altar, and the laver were most holy, because they were closest to God and most directly associated with him. The peace offering was less holy than the other sacrifices, because no part of it ever came into the tabernacle or temple. The same applied for impurity. Some kinds of defilement, like acting as a medium (Lev 20:27) and sacrificing a child to Molech (Lev 10:2), were so absolute that the death sentence was mandatory for them, whereas others, like contact with corpses and venereal discharges, were temporary and readily rectified.

Our Lord did not abolish all this language and thinking, as some contend. His incarnation did, to be sure, change the locus of holiness from the temple to his body (John 2:21) and the focus of defilement from the physical body to the human heart (Heb 9:13-14). It also extended the range of purification and sanctification from the righteous Israelite to the Israelite sinner and the unclean gentile (see Luke 15:1-2; Mark 7:1-30; Acts 10). The blood of Jesus brought about the justification of the ungodly and the cleansing of unclean sinners. Jesus also taught that only those who were pure in heart would see God (Matt 5:8; cf Ps 24:4). He invaded the realm of impurity and cast out the ‘unclean spirits’ from those who were trapped in it. His mission was to destroy them, and they were the first to recognise that (Mark 1:21-27). He washed and cleansed his disciples so that he could sanctify them (John 13:8-11; 15:3; 17:17,19). He was, then, as much priest as he was king.

The language of holiness is therefore the language of worship, for holiness has to do with God’s presence, and access to that presence is given in worship. Where God is present, there holiness is to be found; where he is worshipped according to his word, there his presence sanctifies his people and everything connected with their worship. Since God’s holiness is connected with the mystery of his being, it cannot ultimately be understood rationally and defined abstractly; it can only be adequately apprehended in adoration and truly expressed in praise by those who share in his holiness and stand in his holy presence (Is 6:3; Ps 9:9; Rev 4:9).
Until then the Holy Spirit comforts and encourages Christians through His Word and Sacraments by revealing the Truth of the Son’s sacrifice, resurrection, and perfect love. The Holy Spirit is the inspiration of all the prophets, apostles, and holy writers which all testify and reveal Christ. He gave those writers the very thoughts and words to express and thus, we rightly call their words God’s Word. We trust those words and they are the sole source of all our doctrine and life. The Holy Spirit bestows His own Name and holiness in the waters of Holy Baptism by drowning us with Christ and raising us up again out of the Lord’s death. He calls us His own and enacts the miracle that causes that who cannot, by their own reason or strength, believe in Jesus Christ to not only believe that Jesus is Lord, but more precisely to believe and love that Jesus is their Lord. He is also the efficient cause of the risen Lord’s bodily presence in the Holy Supper. We don’t need, however, to call Him down. He comes down of His own accord and of His own mercy in order to reveal and testify and bestow again to the atoning Sacrifice and resurrection of Jesus Christ.
Still, there is more to the Holy Spirit and His sanctifying than that. He is also the Spirit bestowed by the Christ in the Upper Room for the purpose of Holy Absolution. The Lord Jesus breathed on them and said, “Receive the Holy Spirit. Whosever sins you forgive, they are forgiven.” So also does He intercede and pray for us. This is no small thing. Even as He convicts us of sin and righteousness, even as He rebukes our old man and protects us from our sins while absolving us for Christ’s sake and comforting us with the hope of things unseen, He also advocates for us to the Father and the Son, praying for us with words inexpressible by human tongues. He brings the inmost thoughts and needs of our hearts to the Father in Jesus’ Name. He is the Spirit who lives in us and works in and on us through and Word and Sacrament, who speaks also in the mutual consolation of the brethren, who maintains and blesses the Church on earth. He both prays for us and also causes us to pray and for our brothers and sister, who He declares righteous, to pray for us and the prayer of a righteous man availeth much.
So we life, day by day, hour by hour, and minute by minute, in and by the forgiveness of sins. The Holy Spirit has begun and is growing holiness in us daily by the forgiveness of sins. Meanwhile, “we await the time when our flesh will be put to death, will be buried with all its uncleanness,” when it will no longer need forgiveness, “and will come forth gloriously and arise to complete and perfect holiness in a new, eternal life. Now we are only halfway pure and holy. The Holy Spirit must continue to work in us through the Word, daily granting forgiveness until we attain to that life where there will be no more forgiveness. In that life” we will be His “perfectly pure and holy people, full of goodness and righteousness, completely freed from sin, death, and all evil, living in new, immortal and glorified bodies.”
Come, Holy Ghost, God and Lord with all your graces now out-poured.
In +Jesus’ Name. Amen.