I'm going to tiptoe into this whole religious observance thing...
Every faith has ideas of what an observant member should and should not do. Not working on the Sabbath is a way to honor God's resting on the seventh day after creating the world.
But there seems to be something in the human psyche that loves to codify and stratify and (in general) tell other people in increasingly precise and restrictive form exactly what to do and what not to do, in an anxiety to do the correct thing. So you have people who won't dance, or drink, or kill cows, or play cards on Saturday, or eat pork, or talk to women outside of their family, or do anything that someone once interpreted as doing work on the Sabbath. When these "thou shalts" and "thou shalt nots" are promulgated by people in power within the faith, they often come with a message of "or you're going to hell" or "you're not going to heaven".
But it doesn't mean that everyone of their faith lives by such restrictive rules, of course. And many of those who do choose to keep strict kosher or halal or whatever other forms of piety don't do it because of fear but out of a sense of honor and devotion to their God. Sort of like Lent for many Christians, I suppose.
I respect those who are willing to live with certain constraints on their lives who do it for this reason. I have a hard time with those who do it in a show-offy, holier than thou manner. --And for me, this applies to all faiths, whether Judaism, Islam, the umpty-diddle variants of Christianity, and all the other paths to God.
Sort of interesting timing on this discussion. I am once again working through my One-Year Bible and am in danger of crashing and sinking on the rocky shoals of Leviticus and Deuteronomy. 

 I'm looking forward to the cranky shepherd prophets berating the wealthy and complacent for their selfishness and shallowness, and for their cruelty and coldness toward the poor and unfortunate.