With our celebration of Pentecost on Sunday, we complete our annual celebration of the Easter season.

For the last seven weeks, the Mass and the readings have encouraged us to join those early disciples who, 2,000 years ago, couldn’t believe their eyes, their ears and even the touch of their hands. He who was dead had risen.

In the Gospels, we see how the disciples struggled to adjust to their new understanding of life and death because of the resurrection. But something else became clear to them. Their faith and the way that they lived had to change.

None of us is called merely to live day to day. Instead, we live to become ready for the only thing that matters, standing before Jesus at the moment of judgement asking to be admitted forever to His kingdom.

The conditions for our struggle of faith were set even more clearly with our celebration of this past Sunday: the Ascension of Jesus to His Father. No longer would Jesus be walking and speaking among us as He did before His suffering and death. Neither has He chosen to be coming and going and showing Himself in glory as He did after His resurrection.

With the Ascension, Jesus is with us as truly as He was before. But He chooses to be hidden from the world’s sight. We live now by faith.

We receive the witness of others about Jesus’ teaching and His resurrection. And we are to be witnesses to others.

We live now by faith, not by sight nor by scientific knowledge. That is the challenge of our day and the time and place of history in which we live.

Because of the advances of science over the last centuries, our society is dominated by a climate of thought and discussion that minimizes or even rejects what cannot be measured, calculated or studied by science.

It is only a short step from there to our secularized culture that seeks to eliminate references to God, in speech, in policy, in education and in life. In essence, elements of our society seek to make human knowledge, with its limitations and even its failures, to be the ultimate arbiter even of good and bad, right and wrong.

It is precisely because of this challenge that our celebration of Pentecost is so important. Jesus told us that He would not leave us orphans. He will help us to live for Him even amidst the threats of our secular world.

At Pentecost, Jesus fulfilled His promise that upon His return to the Father, together they would send us the Holy Spirit to remind us of what Jesus said, and to strengthen us. And so the disciples, both joyful but still fearful, gathered to pray and wait.

When they received the gift of the Holy Spirit, they were transformed and given courage to witness to Jesus. The doors behind which they hid were unlocked. They went out to meet with the world.

This is the meaning of our celebration of Pentecost. Year after year, the faithful gather to Christ’s Church and our Catholic faith. We are guided to hold to and defend that faith. We are strengthened to give witness to it in this modern world.

One of the great gifts of the Holy Spirit is courage. We have seen remarkable examples of that holy courage in every age.

In our own time, for example, it takes real courage to witness about preparing for eternal life, or about the plan of God for marriage and the family. As we know, people have sometimes been ridiculed or lost their livelihood for such witness.

Even more, the precious witness of faith even to the point of martyrdom has always been revered in the Church. How often is that a manifestation of the courage given by the Holy Spirit that goes far beyond the human strength of the martyrs? Early on it was Stephen, Peter and Paul. Joan of Arc and Maria Goretti who gave their lives rather than turn from Jesus.

More recently, the photos of Christians in orange jump suits on a Libyan beach being prepared for execution by the ISIS, because of their faith, leaves us astonished by their strength beyond earthly explanation.

Jesus’ death, His resurrection from the dead, His Ascension and the sending of the Holy Spirit at Pentecost are separate moments that can only be understood together. They are the bases of faith and the cause of our joy.

This Easter season has been not just a memory of the past. It is a reassurance of the great gifts placed before us in the present. And it is a reminder of the challenges we face to be faithful to Jesus in our modern world.