Why does the bible say that i should murder my neighbor if he works on sunday?

The LORD then gave these further instructions to Moses: 'Tell the people of Israel to keep my Sabbath day, for the Sabbath is a sign of the covenant between me and you forever. It helps you to remember that I am the LORD, who makes you holy. Yes, keep the Sabbath day, for it is holy. Anyone who desecrates it must die; anyone who works on that day will be cut off from the community. Work six days only, but the seventh day must be a day of total rest. I repeat: Because the LORD considers it a holy day, anyone who works on the Sabbath must be put to death.' (Exodus 31:12-15 NLT)