Here "possession" refers to one's personal property. This idea can be expressed with a verb. Alternate translation: "they will belong completely to me" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
This expression refers to the time when Yahweh will judge and punish the rebellious Israelites, giving victory to the faithful Israelites. (See: [Malachi 4:1-3](../04/01.md))