I heard an atrocious homily this weekend. The deacon was speculating on what the first Christians did in these ten days between the Ascension and the appearance of the Spirit on Pentecost. He said that they were able to select Matthias as Judas' successor during this time because that was just business and didn't require much inspiration. He assured us that they were praying, but without much consolation because the Consoler had not yet come.
The whole mess brings up a real question about how we read the Scriptures in the first place. We hear of many mysteries during the Paschal seasons of Lent, Holy Week and Easter. But the truth of the matter is that all these mysteries, the Passion and death of the Lord, the Resurrection and the sending of the Spirit, these are all really one thing. It is as if we are contemplating one jewel through different facets.
There are intimations of this in the Scriptures themselves. In John the Spirit is handed over from the Cross. Luke alone (except for the longer and doubtful ending of Mark) relates the Ascension and does so twice, once at the end of his Gospel and again at the beginning of the Acts. This alone ought to lead us to see that we are dealing with a narrative device rather than a chronicle. The story of Pentecost is set in the same place as the Last Supper, helping one to see that there is a connection between the farewell of Jesus, the gift of the Eucharist and the sending of the Spirit upon the apostles.
Perhaps this is why the Spirit gave us four canonical Gospels with sometimes differing accounts, so that we might not try to make a timetable out of God's work of salvation. The Passion and death of the Lord, the Resurrection and the gift of the Spirit are one mystery which we come to understand only through a contemplation of its distinct aspects.