38 Here, however, it is expedient to bring under special notice certain matters of moment. First of all, there is the duty of safeguarding private property by legal enactment and protection. Most of all it is essential, where the passion of greed is so strong, to keep the populace within the line of duty; for, if all may justly strive to better their condition, neither justice nor the common good allows any individual to seize upon that which belongs to another, or, under the futile and shallow pretext of equality, to lay violent hands on other people's possessions. Most true it is that by far the larger part of the workers prefer to better themselves by honest labor rather than by doing any wrong to others. But there are not a few who are imbued with evil principles and eager for revolutionary change, whose main purpose is to stir up disorder and incite their fellows to acts of violence. The authority of the law should intervene to put restraint upon such firebrands, to save the working classes from being led astray by their maneuvers, and to protect lawful owners from spoliation.
Source: Rerum Novarum (Vatican.va)