The Sefas Emess asks, why Hashem gave Avraham Avinu such a vague instruction of "לֶך־לְךָ ... אֶל־הָאָרֶץ אְשֶקֶר אַרְאֶךּ", go to the land that I will show you. Why did Hashem not instruct him immediately to go to the land of Canaan?
This can be understood based on the above-mentioned קְדֻשַׁת לֵוִי. Hashem wanted to show us that although one who serves Hashem when everything is smooth and easy, brings great joy and nachas ruach on High, Hashem derives even greater pleasure, k'vayachol, when a person yearns to connect with Him in difficult times when Hashem's Presence is concealed in This World.
Therefore, Hashem intentionally gave him a somewhat cryptic instruction, leaving Avraham Avinu to locate the unknown place for himself. In doing so, Hashem was sending a powerful message to all of mankind, informing them of the immense delight created Above when one serves Hashem in times of difficulty and 'darkness'.
(שפת אמת תרלד ד"ה במדרש שמעי)