What is the grammatical form of "v'Kovi"?
Radak: It is written with one Yud, of the root; the Yud of the plural is omitted, but it is pronounced like the plural (a Tzeirei is under the Yud).
Why does it mention renewal of strength?
Radak: The Resha'im will stumble (30), but Yisrael, who hope to Hashem in Galus, and their strength lapsed, they will get new strength. This is like a tree; if it is cut, it regenerates. Yachalif is a new matter in place of something that passed.
What is "Ever [ka'Nesherim]"?
Rashi: It is a wing. Malbim - it will enable them to fly suddenly to the high places of Shamayim.
Radak citing Rav Sadya Gaon: After 10 years, a Nesher ascends high in the sky. It approaches the heat of fire and casts itself into the sea due to great heat. It sheds its feathers and renews them, and returns to youth. It does so every 10 years, until 100. When it reaches 100, it does like always, and it dies in the sea.
When will they run?
Radak: When they return to their land.
