In Paschal time, the Scripture readings for the Divine Office are taken from the Apocalypse of St John. They are appropriate to the season for, as St Paul has reminded us, being risen with Christ, we are called to "set our hearts on things above, where Christ is seated at the right hand of God".
Most modern scholars hold that the Apocalypse was written near the end of the first century. But Bishop John A. T. Robinson in 1975 argued, with some cogency, that it was written before 70. This was a view of many earlier scholars, including the group known as the Cambridge Triad - Westcott, Lightfoot and Hart - who put it between the death of Nero early in 68 and the destruction of the temple in September 70.
In his Apocalypse, St John provides us with a vivid description of the heavenly liturgy. The angels and saints offer unendingly their tribute of praise and thanksgiving to the eternal Trinity and to the Lamb, who is standing "as one slain before the Throne, ever living to make intercession for us".
Here on earth, we have the counterpart of that heavenly liturgy in the Holy Sacrifice of the Mass, the renewal in sacramental form of the sacrifice of Calvary and our link with the worship of the blessed in Heaven.
As the last book in our Bible, the Apocalypse serves as a worthy finale to the account of God's dealings with mankind, the great drama that began with the creation of man, recorded in the first chapter of Genesis.
I have heard the Apocalypse dismissed by a biblical scholar as "theological science fiction." It is true that St John does use the highly coloured language current in the apocalyptic tradition. But the book contains much of the Scriptural teaching, which, as St Paul wrote to Timothy, "can instruct us unto salvation".
Perhaps its most urgent lesson is that, while we are here on earth, we are caught up in the never-ending war between the Church, which is the Kingdom of God on earth, and the world, which is the empire of Satan, the implacable enemy of God, the prize of the conflict being the immortal souls of men.
Hilaire Belloc has told us that this was the great lesson he learned as a young man from Cardinal Manning, who insisted that this is much the most important war in human history. It has been raging now for two millennia and it will end only on Judgment Day.
This war is a continuation on earth of the conflict in Heaven before time began of which St John has given us an account in chapter 12: "There was war in Heaven. Michael and his angels fought against the dragon, and the dragon and his angels fought back. But he was not strong enough and they lost their place in Heaven." It is to this conflict and its outcome that Christ referred when he said, almost as an aside, "I saw Satan fall like lightning from Heaven".
It could well be that a failure to remember that the Church is ever at war with the world and that, as St Peter put it, "our enemy, the devil, prowls about, like a roaring lion, seeking someone to devour", has something to do with the scandals that have been troubling the Church, especially in the US, in recent years.
There is a striking passage in Apocalypse chapter three. There, after rebuking the Bishop of Laodicea for his lukewarmness, Christ invites him to engage in contemplative prayer, in order to rekindle his earlier fervour. There we read: "Here I am. I stand at the door and knock. If anyone hears my voice and opens the door, I will come in and eat with him, and he with me."
This knock could well signify the "divine touch" which the mystical writers regard as a preliminary to entering on the path leading eventually to the mystical union of pure love, so highly praised by St John of the Cross in his Spiritual Canticle.
This pure, or infused love, the Saint declares, is more precious in the sight of God and more fruitful for the Church and souls than any external work. It is the fruit of a grace that cannot be merited but may be lawfully desired and prayed for, since it is not an extraordinary fervour like a vision but is on the normal path of Christian holiness.
This is the teaching of many theologians and it is confirmed by the fact, attested by St Teresa, that nearly all the nuns in the 17 monasteries she founded had received this grace.
This is that "gold refined in the fire", which Jesus urges the Bishop of Laodicea to buy from him. So while a precious gift, it does 'cost' something.
In its concluding chapters the Apocalypse describes the songs of praise of the Blessed as "like the roar of rushing waters and loud peals of thunder" as they proclaim the final victory of the Lamb and his Bride, the Church. This assurance has helped the faithful in every age overcome the blandishments and threats of the enemy and his human agents.
So it was, for example, with the Archbishop - later Cardinal Thuan - who coped successfully with the years of solitary confinement in a Vietnamese communist prison.
Fr G.H. Duggan SM is a New Zealand writer and theologian.