One should try and strive to follow the ways of our Tzadikim who devoted their lives to serving H'shem in their actions and hearts. They felt the spiritual loneliness of this world and strived to delight only in Him. When we try to achieve these goals we then must trust that H'shem will reward us in the world to come as He did them.
pg445
Nefesh Hachaim
When someone acts with haughtiness it is as though he was Oved Avoda Zarah, denies the existence of H'shem, and committed adultery. The Gemara describes the Shechina's response to haughtiness as "I and he can not live in the same world"
Prologue to Gate 4 Chapter One, pg 119
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