The feast we celebrate today is the reverse of the Incarnation of Jesus. At His incarnation which we celebrate on Christmas, Jesus took on a physical form while still remaining God in heaven. At the Ascension Jesus physically left this earth and took his resurrected body to heaven. Someday when we meet God face to face we will understand how that all worked.
That is difficult to understand but can you imagine what was going through Jesus' disciples minds at the Ascension? They had recently been overjoyed by Jesus' Resurrection, after having experienced the letdown of his crucifixion. They had thought he was to be the rescuer of the Jewish people from the tyranny of the Romans, then he was killed, but after 3 days he rose but now he was going again. Now what were they going to do?
After all those ups and downs Jesus told them what they were to do. Essentially carry out the work he had started, that is, spread the Good News, proclaim his teachings and evangelize by way of following his teaching, witnessing with their lives. Can't you imagine them saying, "that's nice but we are uneducated and there is no way people are going to listen to us." Jesus' response to their unsaid question is in our first reading from Acts which reads: "in a few days you will receive power when the Holy Spirit ... ends of the earth." We know that as unlikely as it seemed, it worked and is still working today. There is a story about the angels questioning how Jesus was planning to continue his work on earth. Jesus response was that his plan was to do that by way of his disciples one of whom had denied him and the majority of who had deserted him. The angels response was, "And what is your backup plan?" Jesus' response was, "There isn't a need for one." He sure has confidence in you and me.
In order for his disciples to carry out his plan he promised to send them the Holy Spirit. That same promise applies to each of us today and so is our individual assignments. We are called to preach the Good News and be Evangelizers with both our words and the way we live. That is the ministries of each of us. You and I receive the gifts of the Holy Spirit just as the disciples did in our Baptism and in our Confirmation, providing us with the ability to carry out individual ministries. The Holy Spirit is there for us to teach via the gifts of wisdom, counsel and understanding, and empowers us via the gifts of courage and strength, and to stay close to Jesus via the gifts of piety and wonder and awe of Him. Just as Jesus left them physically, He was always with them. He isn't with us physically either but He is always with us. In fact we have an advantage over Jesus' initial desciples in that we have the truths Jesus taught in our Christian Scriptures and are able to receive Him in Communion whereas they only had their memories to fall back on.
Are you and I up to the task and what does it mean to each of us. Meeting our task is how each of us accepts our free gift of salvation and is unique for each of us. After attending a convention led by Billy Graham a woman wrote to him. She said, I feel that God is calling me to preach the gospel. But the trouble is that I have twelve children. What should I do? Mr. Graham replied: "Dear lady, I am delighted to hear that God has called you to preach the Gospel. I am more delighted to hear that He has provided you with a congregation." What's my excuse? What's your excuse?