1)
Why does it say "va'Nirdam" (singular)?
1.
Radak: This refers to the king of Gog and Magog, the head of Meshech and Tuval. Since it mentioned "Abirei Lev" (verse 6), it discusses the king, who was boldest.
2)
Why does it say "va'Nirdam va'Rechev va'Sus"?
1.
Rashi: The prefix Vov in va'Rechev is extra, like the Vov in v'Ayah - "v'Eleh Vnei Tziv'on v'Ayah va'Anah" (Bereishis 36:24).
2.
Radak: In addition to the king, also the chariots and horses slept.
3.
Malbim: They were not truly sleeping, just via the rebuke of the mighty Lion, they slept amidst fear, that even the chariot and horse slept, even though a horse is normally awake at night.
