1)
Why does it mention that they forgot His acts?
1.
Malbim: Hashem wanted to save them because He already did wonders for them in earlier days, and they mention Him in their Tefilos - however, they forgot His acts and wonders!
2)
What is the difference between "Alilosav" and "Nifle'osav"?
1.
Malbim (13): Pele is the miracle; Alilos are actions that come from the natures of one Nefesh. They show His Midos and ways. Splitting the sea was the miracle; taking [Yisrael] across (verse 13) was Alilosav, due to His mercy and Chesed.
