The eye is a synecdoche for the whole person. AT: "let us gloat over Zion" or "let us enjoy watching the invaders destroy Zion" (See: [[rc://en/ta/man/translate/figs-synecdoche]])
The farmer puts his sheaves on his threshing floor just before he threshes them. In a similar way, Yahweh will soon destroy the nations. (See: [[rc://en/ta/man/translate/figs-simile]])