Zechariah 12:2

a cup of weakness a vessel of weakness, as in (Exod. 12:22), “in the blood that is in the cup.” weakness an expression of bewilderment, [it means] the clogging of the heart and the limbs, for, like man enwrapped in a garment, they have no strength, as in (Nahum 2:4), “And the cypress trees were enwrapped” ; and (Isa. 3:19) “And the bracelets and the veils.” In the language of the Mishnah (Shabbath 6:6) we find, “Arabian women may go out veiled.” It is involopiment in O.F.

and also on Judah the nations that will be in siege against Jerusalem will impose upon Judah, for the house of David will be inside and the gentiles will besiege them. And also, the children of Judah will come, against their will, to besiege Jerusalem. So did Jonathan render it.

And because of this, He will make Jerusalem a "cup of poison" for all the nations — meaning, a cup of deadly poison, so that whoever drinks from it will die. So too, all those who besiege Jerusalem will be annihilated and perish without any effort. There are those who interpret "cup of poison" as connected to the word "end" (סוף) and "poison" (רעל) as meaning desolation, as in "and the cypresses languish" (Nahum 2:4). According to this, it means that Jerusalem will, at that time, be the end of destruction and desolation for all the nations. As for the phrase "and also upon Judah will be the siege," the commentators explained that Judah, too, will experience the cup of poison, since they will come along with the nations to besiege Jerusalem. Therefore, they too will suffer many troubles and calamities. However, it is more correct to explain that the "cup of poison" mentioned will also affect Judah, and the bet (ב) in "במצור" (in the siege) is a bet of causality — meaning "because of the siege" that will come upon Jerusalem, and because the people of Judah will be there, the cup will also pass over them. And with this, the first question is resolved.