What is the meaning of "Ma'oz la'Tom Derech Hashem"?
R. Yonah: Hashem's Midos are a fortress for a Tom; when his strength falters, Hashem is his strength. Derech Hashem is His Midos - "Hodi'eni Na Es Derachecha" (Shemos 33:13), "Ken Gavhu Derachai mi'Darcheichem" (Yeshayah 55:9).
Malbim: In Hashem's ways they see how He supports the falling and oversees the dejected. All His ways are Chesed, Emes, Tzedakah, mercy and grace. A Tom who conducts with these Midos, he finds strength in seeing that so Hashem conducts the existence.
Why is Derech Hashem a Mechitah for sinners?
Rashi: They do not go on Derech Hashem, and it collects payment from them.
R. Yonah (29-30): Mechitah is fear. They should always fear lest occur to them the end that they cannot escape. Even when they have serenity and strength, Hashem's Midos break their strength and lower their pride.
Malbim: Mechitah is the opposite of Ma'oz. Oz is strength of the Nefesh and Ru'ach. Sinners' ways are the opposite of Hashem's ways and the sustenance of the world.
