1)
Why does it say "El ha'Agalah"?
1.
Radak: This is like Al ha'Agalah, just like "va'Yach Es ha'Pelishti El Mitzcho" (17:49) is like Al Mitzcho.
2)
What is "Argaz"?
1.
Rashi, from Targum Yonasan: It is a box.
