God’s immutability is a third characteristic that we don’t share with him (his third incommunicable attribute) and it refers to his unchangeability. God is already complete and perfect, he has no potential that has not been fully realised. In comparison, we are constantly changing, a truth we can see everywhere – in our children, in our spouse, in our parents.
For God such change is impossible because he already is completely what he is and was supposed to be. Imagine the perfect football player with the perfect kick. If you were to tinker with his kicking action then his kick could only be worsened for it is already perfect; there is literally no room for improvement. In the same way, any variation or change in God could only lead to imperfection because there is no area that he needs to improve in.
This is a great assurance for the Christian conscious of personal sin, for we do not need to fear that God will change his mind. It is exactly this truth that Paul points to when he his encouraging Timothy to endure in the face of hardship and persecution, ‘If we are faithless, he remains faithful – for he cannot deny himself’ (2 Tim 2:13). God knows that we will be unfaithful but because it is in his nature to be faithful and so he will never turn away from his unfaithful people. Moreover, we can have confidence in God’s plan for us, that he does work all things together for the good of his people (Ro. 8:28) and that Christians are ‘predestined according to the purpose of him who works all things according to the counsel of his will’. God’s nature cannot change and his plans and purposes cannot change, he has already worked all things out and no amount of interference from humanity can ever change this. This should be a wonderful comfort for the believer.
However, the more perceptive of you will have picked out a problem: there are many instances in scripture where God does seem to change his mind or regret doing something. For example in 1 Samuel 15:11 God expresses his regret in making Saul King. Do we take this to mean that God has made a mistake? Because if this is so, then we cannot say that God is immutable. Yet only few verses later Samuel tells Saul, ‘the Glory of Israel will not lie or have regret, for he is not a man, that he should have regret (1 Sam 15:29). How do we understand this seeming contradiction? What is illustrated here is that God’s nature and his hidden will do not change, but that his revealed will does.
This should not be seen as a contradiction, but rather as two lines of thought acting as guardrails to keep us on the right path. Although there is real change and partnership and even conflict in history between God and his people, it is never with God’s inner being and never with his ultimate plan. By God’s graciousness we are active participants with him and our involvement in salvation is real, yet he is constant and perfect and so we can have absolute confidence in his immutability and hence in the promises that he has made and that were fulfilled on the cross.
Praise be to our God who allows real relationship with him, while remaining unchanged and perfect, as the hymn proclaims, On Christ the solid rock I stand, all other ground is sinking sand.