Why doesn't God have to keep his own commandments such as "Do not murder"?

In the Bible God gives many commands, but he doesn't seem to have to keep all of them himself. For example in the Ten Commandments God instructs his people not to murder (Exodus 20:13). But God frequently executes people himself, such as when he killed Korah and his 250 followers in Numbers 16. Why doesn't God have to keep his own commandment not to kill? To disobey any of God's commandments is sinful. So how can God ignore them? Does the Bible explain why?