[This post is part of a series about observing a sabbath.]
To observe a sabbath properly, you must rest.
Rest is the core of sabbath keeping and its first dimension. Rest is what makes a sabbath day a sabbath day.
This rest is not merely the rest of sleeping, though a good nap is certainly welcome on a sabbath. It is the rest of stopping.
The Hebrew word (shabbat) behind “sabbath” means “to stop.”
We sometimes use the word “rest” in this way. We might say, “When he was done hammering, he rested the hammer on the workbench.” The rest of sabbath is that kind of rest. It is the rest of ceasing and doneness.
Genesis tells us that when God was done creating the heavens and the earth, he rested from his labors. We read, “ And on the seventh day God finished his work that he had done, and he rested on the seventh day from all his work that he had done.  So God blessed the seventh day and made it holy, because on it God rested from all his work that he had done in creation.” (Genesis 2:2–3). God, of course, is omnipotent, so the rest he took was not the rest of tiredness. It was the rest of stopping and doneness.
This stopping and doneness is the essential core of sabbathing.
A sabbath begins when we stop.
At its first full explanation, this resting/ceasing dimension is clear:
“ Remember the Sabbath day, to keep it holy.  Six days you shall labor, and do all your work,  but the seventh day is a Sabbath to the LORD your God. On it you shall not do any work, you, or your son, or your daughter, your male servant, or your female servant, or your livestock, or the sojourner who is within your gates.  For in six days the LORD made heaven and earth, the sea, and all that is in them, and rested on the seventh day. Therefore the LORD blessed the Sabbath day and made it holy.” (Exodus 20:8–11)
What do we stop? Generally… We stop working. We stop worrying. We stop striving. We stop sinning (works of the flesh).
What do we stop? Specifically… It will vary from person to person. The Sabbath was meant to be holy, and “holy” means “other,” to be separate from the other days of the week. So, what makes your sabbath day “holy” or “other” for you will differ from your neighbor, depending on what your normal days look like.
If you are a professional runner, you probably won’t run on your sabbath. If you have a desk job, you might go for a run on your sabbath. If you anxiously follow the news all week, you would turn it off on your sabbath. If you never read the news, you might leisurely read the paper on your sabbath.
Do you see? “To stop” will look different for different people. To set apart one day in seven will look different depending on your starting point.
But stop you must. It is the essence of observing a sabbath day.