One of the sources of theological reflection that I think is neglected today is hymnody. We tend to look to sermons, books, videos or podcasts as the sources of theological teaching and yet don't pay attention to what we can learn from hymns. However, I think we would benefit if we did and in this article I illustrate why I think this is the case by considering what we can learn if we use two verses from the hymn Glorious Things of Thee Are Spoken by the Anglican hymnwriter John Newton as a starting point.

Newton wrote this hymn in 1799 while he was Vicar in Olney in Buckinghamshire. He based it on two Old Testament passages, Psalm 87:3 and Isaiah 33:20-21 and its first two verses run as follows:

'Glorious things of thee are spoken,
 Zion, city of our God.
 He whose Word cannot be broken
 formed thee for His own abode.
 On the Rock of Ages founded,
 what can shake thy sure repose?
 With salvation's walls surrounded,
 thou may'st smile at all thy foes.
 See, the streams of living waters,
 springing from eternal love,
 well supply thy sons and daughters
 and all fear of want remove.
 Who can faint while such a river
 ever flows their thirst to assuage?
 Grace, which like the Lord, the Giver,
 never fails from age to age.'

In Psalm 87 and Isaiah 33, 'Zion' is an alternative name for the city of Jerusalem, but in the New Testament, as well as referring to this earthly city, 'Jerusalem' is also used to refer to the heavenly city of which God's new covenant people are citizens. Thus, in Galatians 4:26 Paul contrasts the earthly Jerusalem with 'the Jerusalem above' who is 'our mother,' and in Revelation 21:2 John refers to 'the holy city, new Jerusalem, coming out of heaven from God.'

In the light of this New Testament usage, subsequent Christian tradition has understood the references to Jerusalem/Zion in the Old Testament as having dual significance, referring both to the earthly city and to the heavenly city referred to in the New Testament. This is the tradition in which Newton stands and what he is saying is that the promises of God's protection of Jerusalem found in the Old Testament are to be understood as referring also to the protection that God offers to all who belong today to the heavenly Jerusalem.

If we ask what is meant by the heavenly Jerusalem, a common answer is that it refers to the Church. The Church is the heavenly Jerusalem. However, the true answer is more complex than that. This is because the term 'the Church' has two meanings.

As Archbishop Thomas Cranmer noted in the sixteenth century:

'In the Scriptures, the word church has two main meanings ... one of which means the congregation of all the Saints and true believers, who really believe in Christ the head and are sanctified by his Spirit. This is the living and truly holy mystical body of Christ, but known only to God, who alone understands the hearts of men. The second meaning is that of the congregation of all who are baptized in Christ who have not openly denied him nor been lawfully and by his Word excommunicated. This meaning of church corresponds to its status in this life in that in it the good are mixed with the evil.'

To put it another way, there is the invisible Church, which is the mystical body of Christ and which consists of all true believers (regardless of their denomination) and there is the visible Church, the human institution, divided into various denominations, in which those who are true believers and those who are not remain mixed together like the wheat and tares in Jesus' parable (Matthew 13:24-30) until the final judgement.

Newton is referring to the invisible church, since God's promises of protection do not apply to those who do not truly belong to his people. This then raises the question of who belongs to the invisible church. The basic answer to this question is provided by Augustine in his book The City of God, in which he declares that there are 'two kinds of cities created by two kinds of love.' There is the 'earthly city' marked by 'self-love reaching the point of contempt for God' and there is the 'Heavenly City' created by 'the love of God carried as far as contempt of self.' The earthly city 'looks for glory from men' while 'the Heavenly City glories in the Lord.' The invisible Church is Augustine's Heavenly City, the body consisting of those people who lives are marked by love of God rather than love of self, and who seek glory from God rather than from other people.

At this point someone might ask where the grace referred to by Newton comes into the picture. Is Augustine saying that it is our self-generated decision to love God that makes us part of the Heavenly City? The answer is 'No.' For Augustine, as for the New Testament and the orthodox Christian tradition as a whole, we are enabled to love God to the point of contempt of self because in his love for us God gives us new life through Christ and the Spirit through faith and baptism, delivering us from sin and making it possible for us to love him in return. In the words of 1 John 4:19, 'We love, because he first loved us.' It is this gracious, life changing, divine love given to us through the Spirit to which Newton refers when he writes about 'the streams of living water flowing from eternal love' (see John 7:38-39).

A further question which someone might also ask is what it means in practice to live as part of the Heavenly City? If I am a citizen of Zion, what difference should it make? A classic answer to this question is given by another writer from the Early Church, the anonymous author of the second century apologetic work known as the Epistle to Diognetus. He explains that:

'Christians are distinguished from other men neither by country, nor language, nor the customs which they observe. For they neither inhabit cities of their own, nor employ a peculiar form of speech, nor lead a life which is marked out by any singularity. The course of conduct which they follow has not been devised by any speculation or deliberation of inquisitive men; nor do they, like some, proclaim themselves the advocates of any merely human doctrines. But, inhabiting Greek as well as barbarian cities, according as the lot of each of them has determined, and following the customs of the natives in respect to clothing, food, and the rest of their ordinary conduct, they display to us their wonderful and confessedly striking method of life. They dwell in their own countries, but simply as sojourners.

'As citizens, they share in all things with others, and yet endure all things as if foreigners. Every foreign land is to them as their native country, and every land of their birth as a land of strangers. They marry, as do all [others]; they beget children; but they do not destroy their offspring. They have a common table, but not a common bed. They are in the flesh, but they do not live after the flesh. They pass their days on earth, but they are citizens of heaven. They obey the prescribed laws, and at the same time surpass the laws by their lives. They love all men, and are persecuted by all. They are unknown and condemned; they are put to death, and restored to life. They are poor, yet make many rich; they are in lack of all things, and yet abound in all; they are dishonoured, and yet in their very dishonour are glorified. They are evil spoken of, and yet are justified; they are reviled, and bless; they are insulted, and repay the insult with honour; they do good, yet are punished as evil-doers. When punished, they rejoice as if quickened into life.'

This quotation highlights the strikingly paradoxical character of being a citizen of Zion. Those who belong to it live in the world and yet they live in it as resident aliens whose true citizenship lies elsewhere. They conform to the customs and laws of the places in which they live, and yet also live highly distinctive lives in obedience to the laws of God. They do good and yet get insults, persecution and punishment in return, and when this happens, they respond with rejoicing, blessing, honour and love. They die and yet they still live.

In summary, what Newton's hymn is about is the life of the people of God. It is about receiving God's grace, becoming part of his people as a result, and being protected by God as we live as part of his people.

This protection does not mean that nothing bad will happen to us. As the Epistle to Diognetus makes clear (and as many Christians around the world today can testify) bad things may happen to us precisely because we belong to God and live in obedience to his will. Rather, 'salvations' walls' referred to by Newton protect as and when bad things happen to us. They protect us from giving up. They enable us to stay the course as we travel through this world as God's resident aliens. They keep us part of God's people until we reach our final home in the world to come.

Newton's words, and the classical Christian theology underlying them thus provide us with a great promise. However, they also provide a great challenge to us and to other people known to us. The challenge is whether we really are members of the city of God. As we have seen, the issue is not whether we attend a church (since one can attend a church and still not be part of the Heavenly City). The issue is whether we have put our faith in Christ, received his Spirit in baptism, and allowed him to change our lives so that we have begun to become someone who puts God before self and seeks glory from God rather than from our fellow human beings.

If we cannot honestly say that this is the case then we need to change the situation while there is still time. Likewise, if we know others who have not yet put their faith in Christ, received the Spirit in baptism and allowed God to change their lives, then the same applies to them. To quote Isaiah, the message is 'Seek the Lord while he may be found, call upon him while he is near' (Isaiah 55:6).