This prayer was written by Rabbi Shneur Zalman of Liadi, (aka The Alter Rebbe), author of The Tanya:

“Dear God – You commanded us that we should ‘know today, and put it back into our hearts, that You are God – in Heaven above and Earth below – there is nothing else,’ and I’m asking You to help me, to keep my mind really clear, that I might see Your workings in the universe, to feel that You are the life that is invigorating me in this very moment.”

(Cited in A Hidden Light: Stories and Teachings of Early HaBaD and Bratzlav Hasidism, by Rabbi Zalman Schachter-Shalomi and Netanel Miles-Yepez, with a forward by Susannah Heschel, p. 102)