Exodus 35:3
Do not light a fire in any of your dwellings on the Sabbath day.”
What it says
No fire is to be lit in their dwellings on the Sabbath day.
What it is doing
It gives a concrete example of how fully Sabbath rest is to be kept.
In context
1Then Moses assembled the whole congregation of Israel and said to them, “These are the things that the LORD has commanded you to do: 2For six days work may be done, but the seventh day shall be your holy day, a Sabbath of complete rest to the LORD. Whoever does any work on that day must be put to death. 3Do not light a fire in any of your dwellings on the Sabbath day.”