Must God's eternal plan be immutable? I think the short answer to that is we have to ask what we mean by eternal and what we mean by immutable. And if we take the sort of Boethian definition of eternity, where we talk about eternity as fullness of life present at every moment, this idea that to God every when is now, God's plan is immutable in the sense that God is sovereign, that things will not work out the way other than they will not work out in some way other than God knows that they will work out, but I think when we take that view it also allows us to kind of back away from a hard determinism in such a way that there is a dynamism in we can say God's plan is both God's plan is certain, but it is not static, we could say. So, for example, I think when we talk about this we have to consider the notion in the Old Testament of God's changelessness. It's not God being changeless in the Old Testament is not about God being ontologically static. It's about God's faithfulness as a person; it's about God's trustworthiness in delivering on his promises to his people. So, I think the point when we talk about God's plan being immutable, God's eternal plan being immutable, is that we are saying that God is committed to doing what is best, as he knows it, for everything including his people that he has made. And because he is the Maker and he is the overseer of history, things will work out the way he has designed them to work out, but that does not necessitate a sort of micro-managerial view of providence.