To whom is "Oyev" referring?
Rashi and Targum Yonasan: It refers to Par'oh, who was convincing his people to follow him into battle, by promising them to divide the spoils
equally with them.
Rashbam, Seforno and Targum Onkelos: It refers to the people,
who had been convinced to follow Par'oh into battle.
Incorporating the taking of captives (Targum Yonasan).
Who followed the army (Refer to 15:8:1:1*), for the sole purpose of sharing in the spoil.
And who made this declaration when they saw the sea turn into dry land (Rashbam).
Why is this Pasuk written here and not at the beginning of the Shirah, as it refers to the enemy's initial thought in pursuing Yisrael?
Ramban #1 (citing Midrash Chazis) and Targum Onkelos) and Targum Yonasan: Because of the principle 'Ein Mukdam u'Me'uchar ba'Torah' (Torah is not always written in the chronological order).
Ramban #2 and Rashbam
: The decision to chase after Yisrael to fight them and to capture the spoils was made when the Egyptians saw that the sea had split and the sea-bed had dried.
In fact, this was part of Hashem's strategy to lure the Egyptians into the sea to drown them, and was an intrinsic part of the miracle - and it explains why the Pasuk continues "Who is like You among the powers, Hashem!?" (Ramban [Refer also to 14:21:3:1])
What is the meaning of "Torisheimo Yadi"?
Rashi: My hand will impoverish (dispossess) them.
Targum Onkelos: "My hand will destroy them".
Targum Yonasan: "I will destroy them with my right hand".
What is "Achalek Shalal"?
Rashi (14:6): Par'oh said, I will take an equal share of the booty with you, unlike other kings, who take first, as much as they want.
Mechilta: Par'oh said that he will open his treasury and distribute [to those who will fight] silver, gold, precious stones and pearls.