Pastor Dave McCoy preached a message from this passage while my sister was a member of Peoples Baptist in McDonough. She called me up and shared it with me. Praying this request has been repeated many times since her phone conversation.
There have been many sermons, one of which given by Spurgeon is found here in this link.
Putting the application for law enforcement officers is an accurate one because of the context in which David wrote his prayer psalm. David, the warrior, contending for peace and the peace of Israel. I have been amazed at the fitting applications the Bible holds for our law enforcement.
Ellicott's Commentary for English Readers
(17) A token for good—i.e., some sign of continued or renewed providential care and love,
Some grace seen and recognized not only by our mind and heart, but also by those around us, especially those against us.
This has become a prayer for my husband...
" Show him a token for good, LORD, that those who disrespect him, those who don't understand him, those who hate what he stands for , will see your goodness and faithfulness to him and be drawn to your fulfillment of Law, your redemption of men, your blessing on righteousness. Lord, you have helped him and led him to this calling. Continue to comfort and guide. In Jesus name, AMEN(let it be so)"