וּנְתָנָ֛הּ יְהוָ֥ה אֱלֹהֶ֖יךָ בְּיָדֶ֑ךָ וְהִכִּיתָ֥ אֶת־כָּל־זְכוּרָ֖הּ לְפִי־חָֽרֶב׃
And when the LORD thy God delivereth it into thy hand, thou shalt smite every male thereof with the edge of the sword;
Read kabbalistic (mystical) interpretation of Deuteronomy 20:13: and classical mystical sources.