The sword. Put by Figure of speech Metonymy (of Adjunct), App-6, for war.
The sword is without. Reference to Pentateuch, (Deuteronomy 32:25).
Related Commentaries of Ezekiel 7:15
Ezekiel 7:15
15 The sword is without, and the pestilence and the famine within: he that is in the field shall die with the sword; and he that is in the city, famine and pestilence shall devour him.