1)
How will Hashem strike Gog's bow and arrows?
1.
Radak: I will strike them until I make them fall from his hands. I.e. his weapons will not help him; it is as if they are not.
2.
Malbim: He will fight against him until he cannot shoot arrows ? "va'Yatza Hashem v'Nilcham ba'Goyim ha'Hem" (Zecharyah 14:3).
2)
Why does it mention that the bow is in his left hand, and the arrows in his right hand?
1.
Radak: One holds the bow in his left hand, and the arrows in his right hand, and draws the bow string with his right hand (for this requires much strength ? PF).