This refers to the sword of Yahweh which is a metaphor for the soldiers that Yahweh uses to kill a large number of people who have been disobedient to him. AT: "Swords! My soldiers have drawn their swords! They are sharpened for the slaughter" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This speaks of the soldiers killing people as if they were animals devouring their prey. This can be stated in active form. AT: "It is sharp in order to slaughter and to kill people"
# so it will be like lightning
This means that the sword is so shiny that light reflects off of it easily and brightly. AT: "and light reflects off of it as brightly as lightning" (See: [[rc://en/ta/man/translate/figs-simile]])