Here Moses is referring to the members of the tribe of Benjamin. This can be stated in active form. AT: "The ones whom Yahweh loves live" (See: [[rc://en/ta/man/translate/figs-activepassive]])
The abstact noun "security" can be translated using a verb phrase. AT: "lives where no one can harm him" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
# he lives between Yahweh's arms
Possible meanings are 1) Yahweh protects the tribe of Benjamin with his power or 2) Yahweh lives in the hill region of the tribe of Benjamin. In both translations, it means Yahweh takes care of them.