To start, let us consider the early Christian name for this day, Pentecost. The name comes from the Greek word "fifty." Among Greek-speaking Jews, this title was already applied to the Jewish "Feast of Weeks" which began fifty days after Passover. At this feast, weeks after Jesus's Resurrection, the Holy Spirit descended upon the hesitant disciples and transformed them into the living Church (Acts 2:1-21). This makes Pentecost one of the ancient and great feasts of the Church based on Scripture. Later, as Christians developed a calendar, the Church set this commemoration for the fiftieth day after Easter.
We know that the world is filled with many confused and confusing opinions on the Holy Spirit and spiritual matters. And the best way to avoid unsound teachings is to focus on the teachings of Jesus Christ about the Holy Spirit. In today's gospel from John 14:16-17 Jesus says, "And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever; even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you." (KJV)
In these words of our Lord, we are reminded of the origins of the Spirit's work among believers. The Holy Spirit comes among Christ's followers as a gift from God the Father at the intercession of Jesus Christ. Although Scripture speaks of many functions and gift of the Spirit, here our Lord stresses two chief characteristics. The Holy Spirit is our comforter, helper, and guide in appreciating and applying divine truth. And the Holy Spirit comes from the Father and the Son. The Holy Spirit shares the holy nature of the Father and the Son, and He must be distinguished from the spirits of the surrounding world.The Holy Spirit comes from the Father in Christ's name. His work is inseparable from the saving work of the Father and the Son. As the Holy Spirit guides us, He does not bring a new revelation. Instead, the Spirit helps us apply what has already been revealed in the words of Jesus. So Christians must be prudent in their spirituality. The true guidance of the Holy Spirit will always be consistent with the truth of the whole Biblical revelation, especially with Christ's words in the Gospels.