Why is there an extra 'Lamed in the word "l'Chol Cheil Par'oh"?
Rashi: The Torah often adds a 'Lamed'. 1
Ramban: See above, Pasuk 9.
What is the Pasuk referring to when it adds "le'Chol Cheil Par'oh"?
Rashi: It refers to the chariots and the riders that precede it in the Pasuk.
Ramban: Refer to 14:28:1:2.
Seforno: It refers to the chariots and riders (private citizens) who followed the army to the battle-ground. 1
To share in the spoil (Seforno, later 15:9).
Why does the Torah add the words "Ad Echad"?
Chizkuni: It wants to stress that not even one soldier survived. 1