GRACE is a word that is used in many different ways. Throughout the Bible and the history of Christianity, there are two central aspects of the word which dominate. We might distinguish between them by calling one use general, and the other specific.

The first use tells us something about the nature of God in Christian teaching, a nature that is defined by self-giving love. The grace of God, in scripture, is over and over again the lovingkindness of God towards those whom he has chosen to favour. This is seen in his relentless mercy towards his errant children, and his unfailing love in the face of the faithless and loveless behaviour of those whom he has created.

In this sense, the word "grace" describes what God is like, and what God is like is self-giving love. To say this, however, is not to suggest that it is merely an attribute or a description. Love is not an attribute of God in the way that speed is an attribute of cheetahs. Love is what God is, something active and dynamic, and so grace is never simply a characteristic.

The second basic use of the word "grace" is closely related to the first. In fact, it cannot properly be separated from it, since it is an extension of the loving mercy of God which the first use of "grace" describes.

The second idea here is that "grace" can be used to describe a particular gift of God that enables human beings to do and be things that, left to themselves, they seem hardly able to do and be.

We human beings are good at many things, but we are also capable of things that we are not good at achieving. A simple example is loving. Anyone who knows what it is to love can recognise in themselves an ability to be rather extraordinary, to give of oneself without condition or concern for anything other than the well- being and happiness of the object of our love. But the very awareness of our ability to love is also an awareness of our failure to do so most of the time.

Christianity teaches that this distance - we might call it the gap between our human reality and our divine potential - is bridged by the grace of God. In other words, it is overcome by the loving mercy that is God's self-giving love, and by the particular gifts to live in accordance with God's will that characterise the Christian's relationship with God in Jesus Christ.

We can, and should, go further with this second use of the word grace. The distinctive teaching of the New Testament and of the Christian tradition is that the means by which God lifts us beyond ourselves is not an object or a "power". (By "power", here I mean an identifiable quality that allows a person to do something previously impossible, along the lines of the effect that eating a tin of spinach has on Popeye the Sailor Man).

It is the gift whereby God unites human beings with his own life. Grace is the word we use to describe God's infinite love worked out in human beings by drawing those human beings into the perfect fellowship of the Trinity, the eternal selfless love of Father, Son and Holy Spirit.

So, for St Paul, those who are saved by grace through faith are those who are "in Christ", members of the Body of Christ, united with the reality of Jesus Christ crucified and risen. To receive the grace of God is to be invited into God's own self. 

The Revd Peter Groves is Vicar of St Mary Magdalen's, Oxford.

This is an edited extract from Grace: The cruciform love of God (Canterbury Press, £12.99 (CT Bookshop £11.70); 978-1-84825-054-3).