Various conflicts in recent years have reminded us that when civil war breaks out, the normal decencies of life are soon forgotten. The good relations built up between neighbours give way to mutual suspicion and enmity. Even life-long ties can be sacrificed for that mystical sense of belonging to a particular tribe or people, to a particular religion or culture.
What is it that unites people? It may be a common culture, a shared task (such as defending one's country) or perhaps the experience of living under one ruler.
But these are more or less changeable aspects of our lives. The ruler may lose power. The task may end. Even the culture can change and give way to something more pluralistic and less cohesive.
Real unity is based on friendship or love -- seeking the good of others. The unity in a loving family is not something transient. It is based on relations of mutual caring that do not diminish with time.
In an ideal world, society as a whole might be bound by similar relations. Good government can make society more just but, unfortunately, no amount of legislation can ensure friendship and love.
The readings today remind us that Christ is the source of all true unity between human beings. In the first reading Jeremiah laments Israel's lack of good kings. A good king is like a shepherd whose task it is to prevent the flock from being scattered or lost. Jeremiah looks forward to a time when there will be a just and wise king to shepherd his people.
The gospel echoes this metaphor. For Christ is in fact this promised shepherd. St Paul reminds us in Ephesians that the shepherd of Israel is our shepherd too. Christ has removed the barriers between Israel and the Gentiles. The rest of Paul's letter will be concerned with identifying those human sins that threaten our unity in Christ.
The bishops of the Church who follow in Christ's footsteps, obedient to his command to teach and baptize all nations, are the chief shepherds of Christ's flock. But we all share in their task of gathering and uniting God's people. Each meeting with a fellow human being is an opportunity to unite or to divide.
Will our daily contacts with others be divisive or will they serve to unite? Will they increase mutual understanding and strengthen the bonds of friendship or will they add to suspicion, prejudice and antagonism? Will we in our human contacts seek the security of defining ourselves over and against those 'others' who do not belong to our race, religion or culture and have no place in the little worlds we inhabit, or will we be willing to shed the skin of a narrow identity for a truly Catholic social vision, open to the working of God's Spirit in all men and women?
Bringing people together under Christ is no simple matter. It is not only a question of bringing people to the true faith. Faith can only take root in the right kind of soil and the right kind of soil is the knowledge that people are respected and loved.
Even before we teach the truths of our faith there is a need to remove the obstacles that prevent human beings from experiencing the love of God -- poverty, ignorance, prejudice and violence. It is a question of pastoral care, of showing sensitivity to people's needs and sharing peoples burdens.
The building of real community can never be achieved solely by the efforts of a secular society, because a society without faith is a society that places no lasting value on human life and human relations. As history shows, the practice of religion does not alone suffice to produce a truly human society of caring individuals. Religion can all too easily be diverted from its true end. It can become just another culture.
Jesus reminds us that true religion is a question of sharing in the love that the Father offers us through the Son and in his Spirit. The unity that Christ offers us is not just peace on earth but friendship with God and each other for all eternity.