This is a quote from the book "The ​Virtue Of Selfishness" by Ayn Rand
...it is the difference between murder and self-defense. A holdup man seeks to gain a value, wealth, by killing his victim; the victim does not grow richer by killing a holdup man. The principle is : no man may obtain any values from others by resorting to physical force.

The only proper, moral purpose of a government is to protect man’s rights, which means: to protect him
from physical violence — to protect his right to his own life, to his own liberty, to his own property and to the pursuit of his own happiness. Without property rights, no other rights are pos...
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