What is the meaning of "Namu Ro'echa"?
Rashi: Namu is an expression of Tenumah (sleep). Radak - the king's conductors and advisors could not save you from the enemy. It is as if they sleep.
Malbim: Those appointed over the army, they slept.
What do we learn from "Yishkenu Adirecha"?
Rashi: They cannot rise.
Radak: It is as if they dwell in the grave, and died. They cannot help or save you. This is like "Shachnah Dumah Nafshi" (Tehilim 94:17).
Malbim: Since those appointed over the army slept, also your great Giborim lied on their beds and did not go out to fight.
Why does it say "Nafoshu [... v'Ein Mekabetz]"?
Targum Yonasan: They will scatter. Rashi - this is like Nafotzu. All letters pronounced from the same part of the mouth are interchangeable. Zayin, Sin, Samech and Tzadi are all pronounced from the end of the tongue and the bottom of the teeth.
Radak: They increased. This is like "u'Fashu Parashav" (Chabakuk 1:8), "Safoshu k'Eglah Dashah" (Yirmeyahu 50:11). They outnumber you - [you] are spread on the mountains, and no one gathers you [to fight]. Since the leaders were called Ro'im (shepherds), it says that the nation is scattered on the mountain, i.e. like flock without a shepherd, and no one gathers them. Malbim - this is the Nimshal of "Shemesh Zarchah v'Nodad" (17).
Malbim: They rested and did not fight. This is like "Shavas va'Yinafash" (Shemos 31:17).