1)
What will Mitzrayim hear?
1.
Rashi: They will hear that Hashem massacred the whole of Yisrael.
2)
What exactly will Mitzrayim then say? How does "Vesham'u ... ki He'elisa be'Chochacha ... " fit into the picture?
1.
Rashi: Having seen how Hashem took Yisrael out of Egypt with great strength, they will therefore draw the conclusion that, although He was able to defeat the Egyptians, he subsequently killed Yisrael - not because they sinned to him, but - because He was not capable of defeating the Cana'anim. 1
1
Rashi: In fact, this theme repeats itself in the following three Pesukim in a more detailed fashion, as we will now explain.
