Psalm 7:12-13

If he (God) does not relent, he will sharpen his sword; he will bend and string his bow. He has prepared his deadly weapons; he makes ready his flaming arrows.

If he does not relent 
Ezekiel 3:19  "But if you do warn the wicked person and they do not turn from their wickedness or from their evil ways, they will die for their sin; but you will have saved yourself."
Ezekiel 33:9  "But if you do warn the wicked person to turn from their ways and they do not do so, they will die for their sin, though you yourself will be saved."

he will sharpen his sword 
Deuteronomy 32:40-41  "I lift up my hand to heaven and solemnly swear: As surely as I live forever, when I sharpen my flashing sword and my hand grasps it in judgment, I will take vengeance on my adversaries and repay those who hate me."

he will bend and string his bow 
2 Samuel 22:35  "He trains my hands for battle; my arms can bend a bow of bronze."
Psalm 21:12  You will make them turn their backs when you aim at them with drawn bow.
Isaiah 5:28  Their arrows are sharp, all their bows are strung; their horses' hooves seem like flint, their chariot wheels like a whirlwind. (the distant nations)
Isaiah 13:18  Their bows will strike down the young men; they will have no mercy on infants, nor will they look with compassion on children. (the Medes against Babylon)

He has prepared his deadly weapons; he makes ready his flaming arrows 
Psalm 11:2  For look, the wicked bend their bows; they set their arrows against the strings to shoot from the shadows at the upright in heart.
Psalm 18:14  He shot his arrows and scattered the enemy, with great bolts of lightning he routed them.
Psalm 64:3  They (the wicked) sharpen their tongues like swords and aim cruel words like deadly arrows.

(parentheses are mine)

Scriptures taken from the Holy Bible, New International Version® NIV®, Copyright© 1973, 1978, 1984, 2011 by Biblica, Inc.® Used by permission. All rights reserved worldwide. 
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