1)
What are "Shiltei ha'Zahav"?
1.
'Rashi', Rashi (Shmuel II, 8:7): They are [gold] quivers to hold arrows, like it says "Haveru ha'Chitzim Mil'u ha'Shelatim" (Yirmeyah 51:11).
2.
Radak (Shmuel II, 8:7): They were gold shields.
2)
Why does it say that he brought them to Yerushalayim?
1.
Radak (Shmuel II, 8:7) #1: He did not allow them to redeem them, like he let them redeem the captured soldiers (verse 4).
2.
Radak (Shmuel II, 8:7) #2: He brought them to Yerushalayim, to the storehouse of Beis Hashem, for Hekdesh (to build the Beis ha'Mikdash).
