The descent of the Holy Spirit on the Apostles and the Church after the Ascension of Jesus to the right hand of the Father, represented the culmination of nine days of prayer and expectation. It is the source of the devotion called a "novena." While other novenas have come to be, directed to the honor of some saint, or for some spiritual purpose, yet the original novena started at the Ascension and completed at Pentecost is till the Ur-novena from which all take their name.
The readings of the Liturgy of the Eucharist and the Hours in these days are replete with the most wonderful and expectant writings of the New Testament and the Holy Fathers. May the annual celebration of that original outpouring of the Spirit form our hearts more and more into the dwelling place of Christ.