A yeshiva student stopped me at the Kotel and asked; "When we daven (pray) we are supposed to think that we place Hashem in front of us.[i] If Hashem is all, then how am I supposed to picture everything standing in front of me?"
"Yes, Hashem is all, but all is not Hashem," I told him,
I pointed to the prayer book he was holding, "Is this G-d?"
He answered, "G-d is all, so this has to be G-d, too."
"No way!" I said, "G-d is all, but all is not G-d. Is this book infinite?"
He said, "It has to be because the Infinite is all."
I tried to explain, "No, the book is not infinite because the book is not the floor, nor is it anything else. The book is just the book. The Infinite is all including the book, and the floor, and everything else."
I told him, "Place Hashem before us when we daven means that we should talk to Hashem remembering that He is right here with us, right in front of our thoughts."
In truth, Hashem is even closer than that since He fills and surrounds all, but when we pray we want to talk to Hashem as the King, the Creator, our Father. These names point to different attributes that Hashem uses to guide His creation. We address Him with these different "titles" when we pray, but Hashem is not limited to these aspects. He is all, and He is way beyond the all too. The all is but a thought, a word of His."
[i] Psalms 16:8 "I have set Hashem before me…"