Why does it say "Gedol ha'Etzah"?
Radak: His counsels are great, and His deeds are too great to fathom.
Malbim: This hints to a third kind of conduct, with [people] with choice - according to their individual deeds. Even though He is "Gedol ha'Etzah" (Your general counsel encompasses and conducts the Klal from the beginning to the end), You also conduct according to Rav ha'Aliliyah (individual deeds).
What is "ha'Aliliyah"?
Radak: It is the deed.
Why does it say "Al Kol Darchei Bnei Adam"?
Radak: This is unlike they said "Ein Hashem Ro'eh Osanu" (Yechezkel 8:12).
Why does it say "ki'Derachav vechi'Fri Ma'alalav"?
Malbim: You give to an individual based on his intent and his deeds.
