When was the Sabbath first instituted? Our minds leap to the fourth commandment, 'Remember the Sabbath day, to keep it holy.' But it's much earlier in Scripture than that. It goes all the way back to the first Genesis creation story: 'By the seventh day God had finished the work he had been doing; so on the seventh day he rested from all his work. And God blessed the seventh day and made it holy, because on it he rested from all the work of creating that he had done.' Even before the Commandments were instituted in Exodus 20, it's clear that observing it was part of Israelite tradition: they were forbidden from collecting manna on the Sabbath (16:23).

The need for rest isn't just part of the Israelite law code. It's built into the way we're made. And in many ways this day on which God did no work, and on which his people were to do no work, is the most significant of all the creation days in what it tells us about human beings and human flourishing.

1. It tells us we are not slaves to hunger

For far too many people today, the daily struggle for the means of existence is all-consuming. 'Food insecurity' is a fact of life; just getting enough to eat and keep warm and sheltered takes all the time there is. The idea of leisure, a whole day when someone has the choice about what to do and where to go is an unthinkable luxury. When someone's choices are so limited and they live so close to calamity, they are effectively slaves. God's gift of a Sabbath is a powerful call for liberty. It says that in a properly ordered society, everyone would have enough and no one would be forced, by poverty, debt or oppression, to work every hour of every day. There is to be time to play, to create and to choose.

2. It tells us we are not slaves to money

One of the great ironies of life in our time has been the explosion of the leisure 'industry' – and in recent years that's meant time spent online. To say that the gift of leisure is unevenly distributed is an understatement. But there has been a huge increase in ways of passing the time. In the UK, three TV channels have become hundreds. Phones have become mobile computers and computers have become providers of entertainment, information and every type of consumer good. The touch of a few keys can give us whatever we want. Behind this activity lies an endlessly inventive marketing machine, set up by people whose motivation in life is to make us spend more. Ironically, the Sabbath is not just about saving us from being oppressed by too much work; it's about saving us from oppression by too much play. Recovering the Sabbath, for many of us, might mean looking at how we use the internet, what we spend and how we browse.

3. It allows us to make space for God

Many of us live lives that are too busy for reflection. The sort of discipline suggested by ministers who have the privilege of organising their time as they wish is simply beyond us. Work and domestic life leave little time for God, except in the cracks between activities. Of course God is never absent; and many of us have a sense of his presence even when we aren't consciously thinking about him. But paying close attention to him is a different thing entirely. And the Sabbath provides us with an opportunity to do that. The commandment is a statement that we should have time for God, too. Sunday (the Christian Sabbath) is a busy day too, but that's not the point; we might need to choose a different day or time-slot. Its institution, though, says that time for God matters.

'Remember the Sabbath day.' It's easy to forget it in the drive to achieve and accomplish. But it is a gift from God, and not to be taken lightly.

Mark Woods is the author of Does the Bible really say that? Challenging our assumptions in the light of Scripture (Lion, £8.99). Follow him on Twitter:@RevMarkWoods