"In those days Hezekiah became sick and was at the point of death. The prophet Isaiah son of Amoz came to him and said to him, 'Thus says the Lord: Set your house in order, for you shall die; you shall not recover."'
Three verses later, the Lord apparently changes his mind and decides to let Amoz live another 15 years. This sort of self-contradiction is not what we might expect from the Almighty, but it isn't Spirit that changes—it's Hezekiah. Isaiah is basically saying, "choices have consequences," and the king immediately begins to change his choices. He calls upon memories of his best past actions, choosing to live with that awareness rather than anything negative. As a result, his sickness disappeared. It's true for us as well; when we align ourselves with our best choices, our path is much smoother than if we dwell upon enemies, challenges, and fears.