1)
What did Hashem shoot?
1.
Rashi: He cast to the lion's den the ones who caused Daniel to be cast there (Daniel 6:25)
2.
Radak: Past tense is used in place of future, like in most Nevu'os. Just like they shot an arrow (their words) suddenly at me, Hashem will suddenly shoot an arrow at them.
3.
Malbim: He will suddenly shoot an arrow at them, like they wanted to do covertly.
2)
What does the verse teach about their wounds?
1.
Radak: They will come suddenly. "Pis'om" applies to what is before it (shooting an arrow) and after it (their wounds).
2.
Malbim: The traps that they prepared for David, they themselves will strike them.
