“You shall not murder.”
Most of us are more familiar with the King James phrasing of this verse, “Thou shalt not kill.” Using the word “kill” instead of “murder,” however, can be a bit misleading, and cause us to misunderstand the meaning of this commandment. This verse prohibits the intentional, unjustifiable killing of a human being. The Hebrew term used here specifically refers to homicide, not to killing in general. Scripture does not prohibit all killing, whether of animals or even of humans. Many animal sacrifices are prescribed in the Mosaic Law, and several commands call for the death penalty if broken.
Taken in its broader Scriptural context, this commandment tells us that we cannot act as judge, jury, and executioner. While it does not prohibit the death penalty, neither does it necessarily encourage pacifism or vegetarianism. To put it bluntly, we can kill animals for food and even kill other humans, so long as that killing meets certain justifications. (Some examples would be the demands of justice, a just war, or self-defense.) Murder, however, is never justified.