This is why sophisticated contemporary proponents of kenosis theory like Stephen T. Davis simply deny that God is immutable in the classical sense. In their view, God can and does change – not in his character, but in some of his other features. In patristic times, they would have dismissed this out of hand, but I think theists are on strong grounds to think that God changes in some respects. Any real response, any free action on God’s part, is going to involve him changing, is it not? e.g. His creating the cosmos from nothing. To many reflective Christians, trinitarian and unitarian, divine immutability seems dispensable.