From the Treasury of Daily Prayer:

The Church lives and moves and has her being through the gracious inspiration of the Holy Spirit. Without God’s Spirit, no one could come to Christ or believe in Him. The fifty-day celebration of Easter ends with this joyous festival. The risen and ascended Savior has sent the Holy Spirit to be our Sanctifier, entering our hearts at Holy Baptism, nurturing us through the Word, and enabling us to understand the Gospel and to live a life that honors God and serves our neighbor.