Know this day and consider it in your heart that Hashem is G-d in heaven above and on earth below; there is no other. (Deuteronomy 4:39)
The following excerpt is from the book The Essential Rabbi Nachman, translated by Rabbi Avraham Greenbaum.
"The only way to know G-d is through complete faith. Only faith can bring you to true knowledge and perception of G-d's greatness" - Rebbe Nachman of Breslov