When reading this proverb one gets the idea that the wicked pay the price for the salvation of the righteous - but that is not what the Scriptures are saying here. What is being communicated is that often the wicked pays the price for how they treat the righteous. That cost is usually to have their own evil plans come down upon their own head. The best example of this is found in the book of Esther.
Haman is the villian in the book of Esther. It is his evil mind that hatches the idea of getting revenge on Mordecai for his supposed irreverence by destroying not only him, but his entire race. Money is given to the king - a bargain is struck - letters are written - and soon the entire Jewish people are under a death sentence in the future. The rest of the book of Esther shows us God's sovereignty through the hand of His providence working again and again on behalf of His people Israel. In the end, the plot put in place by Haman comes down upon his own head - destroying not just him, but his entire family before the book ends.
Throughout history attempt after attempt has been made to destroy the work of God by destroying the people of God. Again and again God has worked wonderfully to deliver His people individually and coporately. Daniel is thrown into a lion's den for his audacity to pray to anyone besides the earthly king - and yet is delivered by the hand of God. Who is destroyed in this plot? The very men who planned and put it into place where thrown into the lion's den and crushed and killed once Daniel was lifted out. Nebuchadnezzar casts the three friends of Daniel, Shadrach, Meshach, and Abed-nego into a firey furnace thinking to kill them in the process for not bowing down and worshipping his idol. Once his dastardly deed is done he is shocked to see the men walking around the fire with the pre-incarnate Christ unharmed - while the brave soldiers who threw them in are killed instantly in their task. Ahab sends 50 men to forcefully bring Elijah to himself - and yet fire falls from heaven and consumes two groups of them as they draw near. These historical accounts happen throughout the Scriptures revealing that the wicked and treacherous become the payment for their own wickedness while the righteous and upright are delivered.
It is an unwise thing to try to annihilate the people of God. It is also an unwise thing to attempt to kill His spokesmen, the prophets. Those who try will learn an oft taught lesson that God will deliver His people - and bring the ways of the wicked upon their own heads and even at times on the heads of their children and followers. The truly wise man honors the upright and the righteous - knowing that their defender is strong - and also knowing that He can take any plot and any plan and turn it around so that the destroyer becomes the destroyed.