Verses with the word firebrands in the Old Testament (3 verses):

Judges 15:4
And Samson went and caught three hundred foxes, and took firebrands, and turned tail to tail, and put a firebrand in the midst between two tails.

Proverbs 26:18
As a mad man who casteth firebrands, arrows, and death,

Isaiah 7:4
And say unto him, Take heed, and be quiet; fear not, neither be fainthearted for the two tails of these smoking firebrands, for the fierce anger of Rezin with Syria, and of the son of Remaliah.