en_tn_condensed/rev/09/14.md

The voice said

The voice refers to the speaker. Alternate translation: "The speaker said" (See: rc://en/ta/man/translate/figs-synecdoche)

the four angels who are bound

The text does not say who has bound the angels, but it implies that God told someone to bind them. This can be stated with an active form. Alternate translation: "the four angels whom God has commanded them to bind" or "the four angels whom God has commanded someone to bind" (See: rc://en/ta/man/translate/figs-activepassive)