פירוש על שמות 14:23

כל סוס פרעה (The word סוס is singular) — But was there only one horse? But the use of the singular teaches us that they were all accounted before the Omnipresent as only one horse (cf. Mekhilta d'Rabbi Yishmael 15:1:6).

וירדפו מצרים, Egypt pursued, etc. Even though the Torah says: "the cloud remained in place" (verse 20), what is mentioned here occurred in daylight already at a time when the cloud was not as impenetrable so that the Egyptians could begin to discern where the Israelites were positioned. This enabled them to start their pursuit.

Was there only one horse. . . [Rashi is asking:] כל indicates something that is two or more. Why then is סוס written in the singular form? Rashi did not ask this on כל סוס רכב פרעה (v. 9), because there, כל refers collectively to horse and chariot. But here the question arises, since it is written סוס , in the singular form. This resolves Re”m’s difficulty; see there.

ויבאו אחריהם, “they followed after them;” They might not have done so knowingly, but seeing that everything in front of them was darkness, they did not realise that they had done so until they were into what had been sea moments before.