1)
Why was he called "Ish ha'Elokim"?
1.
Rashi citing Targum Yonasan: He was a Navi of Hashem.
2)
What is "Shomer ha'Saf"?
1.
Rashi citing Targum Yonasan: It is a treasurer.
2.
Radak: Saf is an encompassing term for Kelim of the house, wine and other matters.
3)
Why did he bring them to the chamber above Shomer ha'Saf?
1.
Malbim: It is to publicize the matter. All who enter and leave will know.