“You must not murder.” This is the sixth of the Ten Commandments. The “you” is singular from the singular verb. See commentary on Exodus 20:3, “you.”
“murder.” The Hebrew word translated murder in the REV, but “kill” in the King James Version, ratsach (#07523 רָצַח) and it can mean “kill” or “slay,” either on purpose or accidentally. Ratsach, like many other words, has a wide range of meaning, and thus its meaning in a particular verse must be determined from the both the immediate and remoter contexts. Thankfully, the Bible has a lot to say about murder, manslaughter, the execution of criminals and killing in war, and it is easy to tell by studying all the verses on the subject that the Sixth Commandment means not to take a life unjustly. In this context, ratsach should be translated “murder,” and it is in most modern versions (cp. CJB; HCSB; ESV, NASB; NET; NIV; NKJV; Rotherham; YLT).
Thankfully, most Bible commentators are not confused by the sixth commandment even when it is translated as “You shall not kill.” Maxie Dunnam wrote about the Sixth Commandment, “According to Genesis 9:6, this commandment did not prohibit the death penalty. It is obvious in the Old Testament that this [Sixth Commandment] was not a prohibition against all killing, only unauthorized killing (Mastering the Old Testament: Exodus, Word Publishing, Dallas, TX, 1987, p. 263).
Since killing in criminal execution, in self defense and in war are condoned in Scripture, it is hard to see how “You shall not kill” is an acceptable translation of ratsach in the Sixth Commandment. There is no question that the average reader gets the wrong idea from “you shall not kill,” and instead of correctly concluding that accidental killing and suicide are being included with murder, the modern reader wrongly concludes that self-defense, the execution of criminals and killing in war are forbidden by God.