The sentiment appears really early on in the book of Job which has the character Elihu jumping in to what was effectively an adaptation of the earlier dialogue on the injustice of suffering in the Babylonian Theodicy to claim that God's purpose and motivations are unknowable because why it rains and where snow comes from is beyond human understanding.

Now that why it rains is literally a nursery rhyme, maybe we should really adjust our thinking about just how undecipherable a potential creator of the universe is.

For example, religious traditions that believe God is light (1 John 1:5) and believe it was an intelligent designer of the universe might want to think a bit more on the design detail that light when unobserved can be more than one thing at once, and can even be different things to different eventual observers. At very least, you'd think that would give them pause in their commitment to the idea of absolutely defining who or what their God is for everyone else.