With these words begins one of the ten great tests of Avrohom. The Ramban explains that these were trials by fire, designed to bring the Avrohom’s greatness to the surface, taking it from the potential to the actual. They helped form him into the singular tzaddik that he became.
Rashi notes that in this test, HASHEM is very expressive about the place where Avram is leaving from, but fails to mention where he is to go to. “Leave your land, your birthplace, your father’s house, and go. . .” Rashi explains that this was all part of the test, and added to the reward he would receive when he passed. Each description of where he was leaving from increased his longing and attachment to it, making it more difficult. Not telling him where he was going to made it even more difficult because now he had to blindly listen to HASHEM. Rashi continues that this is similar to the akeidah when HASHEM challenged Avrohom: “Take your son, your only son, the son that you love.” Each phrase further increased the test because it highlighted and stirred up the love Avrohom felt for his son. So too here: “your birth place, your homeland...”
When we focus on who Avrohom was, this Rashi is difficult to understand. The Avos were spiritual giants, men whose feet may have been on the ground, but who lived up in the heavens. What difference did it make to Avram where he was leaving from? He didn’t really exist there; he lived in a world of spirituality, barely cognizant of his physical surroundings. And what makes this question even more pointed is that it is hard to imagine that Avram was particularly attached to either his birthland or his father’s house.
