Here is a nice little quote from Paula Rhinehart, that illustrates a much more modern understanding of this concept:
God does not allow us to reduce Him to a size and a shape we can manage. He moves in our lives in ways that burst our categories and overwhelm our finiteness. When we realise He’s bigger than anything we can get our minds around, we can begin to relax and enjoy Him.
Of course, it is almost a given that Rhinehart is referring to the Trinity, but should not a Unitarian perspective also embrace the God-Jesus relationship as "ineffable"? Either way, I basically agree, and this paper should be understood to operate within this boundary. The more we know, the more we know how little we know.