Why does the Torah write "Kol Sus Pharaoh" (singular)?
Rashi: Because in the Eyes of Hashem, all of Pharaoh's horses were like one horse.
QUESTIONS ON RASHI
Rashi writes: "Kol Sus Pharaoh - Was it [only] one horse? Rather, this [term in the singular] indicates that all of them were like only one horse, before Hashem." The Mechilta (unlike Rashi) does not give this interpretation here, but rather on the Pasuk "Sus v'Rochvo Ramah ba'Yam" (15:1). Why?
Gur Aryeh: In our verse, the term "Sus" (singular) may simply be referring to the entire set of horses, acting together as one unit. The Torah speaks this way often (e.g., in Bereishis 32:6, 1 and even in 14:9 above). It is only verse 15:1, "... horse and its rider, He overpowered into the sea," which requires interpretation. When one opposes horses in battle, one cannot face off against all of them together; rather one must topple each one separately - unless we speak of Hashem, Who is All-Powerful, and before Whom they are as easy as one horse.
See Rashi there.
