The new issue of Credo Magazine is titled The Immutability of God. The following is an excerpt from Peter Sanlon’s article, Immutability, the Promises of God, and the Christian Life. Peter Sanlon (PhD) is Director of Training for the Free Church of England. He holds theology degrees from Cambridge and Oxford University. His doctoral research has been published as Augustine’s Theology of Preaching. He is also author of Simply God: Recovering the Classical Trinity.


For many today, the Christian life itself is cut loose from the doctrines of God’s promises. When this happens fallen humanity is thrown upon its own resources and the promises of the world. The result is that the Christian life becomes a dry husk of human effort, or a chaotic worldly grasping after the latest idea that comes along. The only way to live the Christian life with confidence is to believe God’s promises and to do so assured that they come to us with the full immutable power of the perfect free God who speaks to us in grace. Isolating any of the doctrines before us–God’s immutability, promises, or the Christian life ossifies all the doctrines and robs us of the spiritual power we need in life and death. Isolating any of the doctrines before us–God’s immutability, promises, or the Christian life ossifies all the doctrines and robs us of the spiritual power we need in life and death.

Energizing the Doctrines

Recognizing the links between the doctrines before us energizes and refreshes each of them. The immutable God who grants us soteriological promises is qualitatively different from an immutable God who does not do so. The Christian life attempted in isolation from God’s promises is fundamentally different from one that depends upon the promises. Depending on promises God has made, but neglecting to trace them to the immutability of God in himself, drains those promises of the power God ordinarily grants them. When the links are established in our consciousness, God takes his proper place–we are empowered by him to believe his promises. In this lies the mystery that the Christian life is lived by us in a way that is empowered by God. Faith is the most personal intimate action a person can make – yet, it is a spiritual work of salvation wrought in us by God.

Trinitarian Immutability

The Trinity is revealed in the economy of salvation. In the incarnation, Father, Son and Spirit are each revealed to be divine in a way that upholds monotheism. Even while all works of God are inseparably the work of each person, so the distinctiveness of Father Son and Spirit gives rise to each being associated with particular actions.

It is possible to conceive of a doctrine of immutability that ignores the Trinity revealed in salvation’s economy. Such a “god” is distant, inert, impersonal and ugly. When people reject the doctrine of immutability they usually assume they are prizing the barnacles of Greek philosophy from the doctrine of God. In reality they are prizing the doctrine of God off from that to which it ought to be fixed–the Trinity revealed in the economy of salvation. The immutable God is Trinitarian. The only way to live the Christian life with confidence is to believe God’s promises and to do so assured that they come to us with the full immutable power of the perfect free God who speaks to us in grace. Click To Tweet

The link between immutability and covenant promises ensures this is so at a deep level. The covenant promises are to be traced back to the inner reality of the Trinity. It is not just that the promises are reliable because they come from an unchanging God; much more delightfully the promises of God reveal something of the unchanging beauty of the God who is Trinity. All three persons are fully committed in their freedom of grace to bring the covenant promises to fulfillment. The promises arise not from monistic will or decision, but immutable Trinitarian love. The immutable Trinity is unchanging and so forever what he is–one God in three divine persons eternally pouring out infinite, costly love upon a creation that is itself a gift of grace. In an immutable timeless act, the unbegotten Father begets the Son, the Son is begotten of the Father, the Spirit is spirated from Father and Son. All this is perfect love (1 Jn. 4:8-13).

So fulsome and perfect is this Trinity of love that it must reach out to sinful rebels in covenant promises. The words are not empty promises as Father, Son, and Spirit commit in loving omnipotence to overcome all that would thwart their purposes. If we attempt to contemplate God’s immutability apart from his covenant promises, we gaze at a conception of divinity that is brittle, non-relational, and overly comprehensible to creatures. Only when we gaze at God’s immutability through his Trinitarian covenant promises can we discover that immutability, like other attributes of the divine being “have true meaning only insofar as their concrete manifestation is taken up into the sway of divine love” (Pannenberg, Systematic Theology, 1:445).

When God’s immutability is divorced from covenant promises, the vision of immutability tends to lack the Trinitarian form which otherwise arises from the economy of salvation in which the promises feature. The confidence we have in God keeping his promises is greatly enriched when we view the promises as not only coming from an immutable God, but a Trinitarian God in which each person is fully alive and committed to fulfilling covenant promises. Our hearts are warmed by the sense that not only are we the beneficiaries of promises assuredly kept by the immutable God–we adore and wonder at the traces of God’s inner Trinitarian being as he is revealed in the treasured promises.

God is Immutably for Us

The exercise of reading through this essay is itself a disciplined work of theological reasoning. The careful consideration of how God’s immutability and covenant promises are situated and related one to another, has an impact on our Christian living. We begin to sense that our greatest needs are indeed fully and unreservedly met in God. We discover that God is revealing himself to us as we ponder his immutability. We are relieved to sense that God is for us as he makes promises to us. In his Trinitarian inner reality, God is immutably for us. He will go to hell itself to give himself for and to us. Consider our weak frames and sinful lives and all that seems impossible to believe. Ponder the immutable God who is loving Trinity and promises to do it–that shapes and empowers the Christian life.

Read Peter Sanlon’s entire article in the new issue of Credo MagazineThe Immutability of God.