take the law into one's hands

1. Also, take the law into one's own hands. Replace the established authority with one's own, as in While the captain was on shore the sailors took the law into their own hands and sneaked the prisoner off the ship. Generally indicating disapproval of doing something forbidden, this idiom was first recorded in 1606.

Example Sentences

“Many understood this statement as a call to wastefully spill blood and take the law into one’s hands by implementing killing operations.”

From Fox News