en_tn/zec/12/05.md

say in their hearts

Here "hearts" represents a person's mind. Alternate translation: "think to themselves" or "say to themselves" (See: rc://en/ta/man/translate/figs-metonymy)

are our strength

The abstract noun "strength" can be stated as "strong" or "encourage." Alternate translation: "make us strong" or "encourage us" (See: rc://en/ta/man/translate/figs-abstractnouns)

Yahweh of hosts, their God

"Yahweh of hosts, the God they worship"