The Homily is part of the Liturgy and is highly recommended, for it is necessary for the nurturing of Christian life. It should be an explanation of some aspect of the readings from Sacred Scripture or of another text from the Ordinary or Proper of the Mass of the day and should take into account both the mystery being celebrated and the particular needs of the listeners.So, for a feast like that of All Saints, it is quite legitimate to use the Liturgical texts other than the readings to explain exactly what it is that the feast celebrates. And this is an interesting exercise, and one that itself is not lacking in Scriptural reference.
From the Preface, which has a title in the Missal of "The glory of Jerusalem, our mother":
... today by your gift we celebrate the festival of your city, the heavenly Jerusalem, our mother ... Towards her we eagerly hasten as pilgrims advancing by faith ...The proper prayers of the Mass also indicate an important characteristic of the Feast, namely that of our need for the intercession of the saints. The Prayer over the Offerings, for example:
May these offerings we bring in honour of all the Saints be pleasing to you, O Lord, and grant that, just as we believe the Saints to be already assured of immortality, so we may experience their concern for our salvation.What is striking too is something that emerges from the hymns at Vespers and Lauds for the feast day. It is very apparent in the Latin hymns, rather less so but not absent from the hymns in the English "Liturgy of the Hours". These hymns refer in turn to the Virgin Mary, the angels, patriarchs and prophets, the apostles, martyrs and confessors, virgins and religious, in turn asking each category of saint to intercede for us.
I suspect that it is common place for the feast to be explained as a celebration of those who are in heaven but have not been formally declared saints by the Church - and it is certainly that. It may well refer to people whom we have known and who have lived their Christian vocation in a way that has inspired others - and I do feel that this "ordinary sanctity" of parish life can too often go unnoticed.
But the office hymns suggest challenging models of the road to sanctity followed by the saints. The celebration of the feast asks us to learn how these models can be lived in the contemporary world. Those who live the married vocation in fidelity to Catholic teaching, for example, might well in future times be seen as confessors of the faith in their particular circumstances of life; current events in the Middle East also clearly show confessors and martyrs in the more usual sense.
All Saints is a good example of a feast day on which a homily limited to explaining the Scripture readings will miss out important aspects of what the feast itself actually celebrates.