Why is Bavel compared to a gold cup in Hashem's hand?
Rashi: Until now, through it, Hashem intoxicated the entire land with wine of anger.
Radak: Clear wine is called gold, due to the clearness of gold. Also clear oil is metaphorically called gold - "ha'Merikim me'Aleihem ha'Zahav" (Zecharyah 4:12). Also the clear wind from the north is called gold - "mi'Tzafon Zahav Ye'eseh" (Iyov 37:22). It says "b'Yad Hashem", for Melech Bavel was Hashem's Shali'ach to destroy nations. This is like it says above ("Kach Es Kos ha'Yayin ha'Chemah ha'Zos mi'Yadi v'Hishkisah Oso Es Kol ha'Goyim" (25:15); also here it says "me'Yeinah Shasu Goyim"!
Malbim: It is compared to gold, which is a strong metal 1 . It says "b'Yad Hashem", for it is the staff of His anger.
Gold is very soft! Perhaps he means super-refined gold, which is strong; refer to Shemos 25:11:152:1*. (PF)
What is the meaning of "Yis'holelu Goyim"?
Rashi: They became intoxicated and foolish.
Radak: They will go crazy. This is like "Holelus v'Sichlus" (Koheles 1:17), "v'Shasu v'His'go'ashu v'His'holalu" (above, 25:16). They are compared to clear, clean wine, for "ha'Tzur Tamim Pa'alo" (Devarim 32:4).
