What are "Mitz'adei Gever"?
Rashi: It is one who is Gibor (mighty) in Yir'as Hashem.
Radak: It is a Tzadik who, with his good deeds, overpowers a Rasha.
Radak citing R. Shlomo ben Gevirol: They are the ways of serving Hashem. Do not say that they are "me'Hashem", and not from free choice. Rather, Hashem prepared the reward or punishment for man.
What is the meaning of the verse?
Radak: Hashem guides the Tzadik's steps, and desires his ways - "v'Chol Asher Ya'aseh Yatzli'ach" (1:3). Mitz'adei and Darko teach that every motion in all his matters will succeed.
Radak citing R. Shlomo ben Gevirol: Hashem created the Nefesh without any lack; when it leans to the esteemed attributes and good conduct, he is pleasing to Hashem, and Hashem desires his ways.
Malbim: Hashem prepared in front of man the path that he will want, and enables him to go on the path - "Lo l'Adam Lo l'Ish Holech v'Hachin Es Tza'ado" (Yirmeyah 10:23).