In the first book, O Theophilus, I have dealt with all that Jesus began to do and teach, until the day when He was taken up, after He had given commandment through the Holy Spirit to the Apostles whom He had chosen.
In the Rosary, the Glorious Mystery of the Ascension is traditionally associated with prayer for the virtue of Hope. Hope is oriented not so much toward the future, as toward the fact that the same God we have known and know now is not going to abandon us. It is curious that this faith that Jesus will not abandon us is associated with the moment in the gospel where Jesus leaves us. But, as Luke makes clear, Jesus is not really leaving. For the gospel he has just written only tells us of what Jesus “began” to do and teach. His entire earthly ministry is only the spark. The Church, filled with His Spirit, is the Fire and He is now to continue His work in a way more intimate with us than it was during His earthly ministry. That is why He Himself said, “But now I am going to Him who sent me; yet none of you asks me, ‘Where are you going?’ But because I have said these things to you, sorrow has filled your hearts. Nevertheless I tell you the truth: it is to your advantage that I go away, for if I do not go away, the Counselor will not come to you; but if I go, I will send Him to you” (Jn 16:5-7).