Why did Hashem not tell him immediately where to go?
Rashi: So that people would not be able to say that Hashem shocked him suddenly and confused him, and that had he had time to think it over, he would have refused. 1
Seeing as Hashem did not actually inform him that he had arrived at his destination, how did he know that he had?
Rashi and Ramban #1: He saw a cloud enveloping Har ha'Moriyah.
Ramban #2: He saw Eretz ha'Moriyah, which he recognized.
What is the significance of the word "me'Rachok"?
Seforno: Hashem enabled Avraham to see Har ha'Moriyah whilst it was still outside his range of vision, 1 and he understood himself that this was where the sacrifice would take place.
רש"י: ביום השלישי...שלא יאמרו הממו וערבבו פתאום: למה דוקא שלושה ימים?
גור אריה: כך מצאנו לעניין תפילה שעד שלושה ימים בבואו מהדרך, אין דעתו של אדם מיושבת עליו.