'Themselves' in the Bible

Many nations shall join themselves to Yahweh in that day, and shall be my people; and I will dwell in the midst of you, and you shall know that Yahweh of Armies has sent me to you.

I asked him the second time, "What are these two olive branches, which are beside the two golden spouts, that pour the golden oil out of themselves?"

It will happen in that day, that I will make Jerusalem a burdensome stone for all the peoples. All who burden themselves with it will be severely wounded, and all the nations of the earth will be gathered together against it.