What is the tense of "Yer'u"?
Rashi: It is a command - fear Him!
Why is there no vowel under the Reish in "Yer'u"?
Radak: The Aleph is silent (has no vowel); the Shuruk applies to the Reish. This is to distinguish it from Yir'u (from the root Ra'ah (seeing), in which there is a Sheva under the Reish, and the Shuruk applies to the Aleph).
Who are "Kedoshav"?
Radak: They are people who withhold themselves from many desires, like a Nazir who refrains from wine is called "Kadosh Hu la'Shem" (Bamidbar 6:8).
Why does it say "Ki Ein Machsor li'Re'av"?
Radak #1: You Kadosh people, who are satisfied with a small amount in this world, and do not chase food, you will not lack food.
Radak #2: If you fear Hashem alone, He will supply your needed food.
Radak #3: David said so about himself. He was exiled amidst the Pelishtim, and had no friends there to give to him food. Because he feared Hashem, he did not lack food.
Malbim: Nochrim who became 'Kadosh' to idolatry separated from civilization. They did not fear Hashem; they feared folly, and harm to themselves. They lacked two matters. (a) They chose to separate from all worldly pleasures. (b) Since they did not engage in their needs, they lacked greatly amidst necessity, and needed to eat Rosem roots. Yir'ei Hashem need only guard the Mitzvos; they need not flee from civilization. They have no lack via choice - the Torah did not command to lack good! They have no lack amidst necessity - refer to 34:11:3:1.
Is it easy to become a Yare Shamayim?
Mesilas Yesharim (Perek 24): This was easy only for Moshe, due to his great clinging to Hashem. It is proper for every Chasid to strive to attain what he can [of Yir'as Shamayim].
