The color Blue probably refers to the "royal" color, and that may be where the phrase "Blue Law" comes from originally. I think however the concept of forcing or insuring a day off each week comes direct from the Bible.
"These are the things which the LORD has commanded you to do. 2 Six days shall work be done, but on the seventh day you shall have a holy sabbath of solemn rest to the LORD; whoever does any work on it shall be put to death; 3 you shall kindle no fire in all your habitations on the sabbath day."
"The LORD said to Moses, 13 "Say to the people of Israel, 'You shall keep my sabbaths, for this is a sign between me and you throughout your generations, that you may know that I, the LORD, sanctify you. 14 You shall keep the sabbath, because it is holy for you; every one who profanes it shall be put to death; whoever does any work on it, that soul shall be cut off from among his people. 15 Six days shall work be done, but the seventh day is a sabbath of solemn rest, holy to the LORD; whoever does any work on the sabbath day shall be put to death. 16 Therefore the people of Israel shall keep the sabbath, observing the sabbath throughout their generations, as a perpetual covenant. 17 It is a sign for ever between me and the people of Israel that in six days the LORD made heaven and earth, and on the seventh day he rested, and was refreshed.'"
While the people of Israel were in the wilderness, they found a man gathering sticks on the sabbath day. 33 And those who found him gathering sticks brought him to Moses and Aaron, and to all the congregation. 34 They put him in custody, because it had not been made plain what should be done to him. 35 And the LORD said to Moses, "The man shall be put to death; all the congregation shall stone him with stones outside the camp." 36 And all the congregation brought him outside the camp, and stoned him to death with stones, as the LORD commanded Moses.
12 "'Observe the sabbath day, to keep it holy, as the LORD your God commanded you. 13 Six days you shall labor, and do all your work; 14 but the seventh day is a sabbath to the LORD your God; in it you shall not do any work, you, or your son, or your daughter, or your manservant, or your maidservant, or your ox, or your ***, or any of your cattle, or the sojourner who is within your gates, that your manservant and your maidservant may rest as well as you. 15 You shall remember that you were a servant in the land of Egypt, and the LORD your God brought you out thence with a mighty hand and an outstretched arm; therefore the LORD your God commanded you to keep the sabbath day.
14 Remember me, O my God, concerning this, and wipe not out my good deeds that I have done for the house of my God and for his service. 15 In those days I saw in Judah men treading wine presses on the sabbath, and bringing in heaps of grain and loading them on asses; and also wine, grapes, figs, and all kinds of burdens, which they brought into Jerusalem on the sabbath day; and I warned them on the day when they sold food. 16 Men of Tyre also, who lived in the city, brought in fish and all kinds of wares and sold them on the sabbath to the people of Judah, and in Jerusalem. 17 Then I remonstrated with the nobles of Judah and said to them, "What is this evil thing which you are doing, profaning the sabbath day? 18 Did not your fathers act in this way, and did not our God bring all this evil on us and on this city? Yet you bring more wrath upon Israel by profaning the sabbath." 19 When it began to be dark at the gates of Jerusalem before the sabbath, I commanded that the doors should be shut and gave orders that they should not be opened until after the sabbath. And I set some of my servants over the gates, that no burden might be brought in on the sabbath day. 20 Then the merchants and sellers of all kinds of wares lodged outside Jerusalem once or twice. 21 But I warned them and said to them, "Why do you lodge before the wall? If you do so again I will lay hands on you." From that time on they did not come on the sabbath.
19 Thus said the LORD to me: "Go and stand in the Benjamin Gate, by which the kings of Judah enter and by which they go out, and in all the gates of Jerusalem, 20 and say: 'Hear the word of the LORD, you kings of Judah, and all Judah, and all the inhabitants of Jerusalem, who enter by these gates. 21 Thus says the LORD: Take heed for the sake of your lives, and do not bear a burden on the sabbath day or bring it in by the gates of Jerusalem. 22 And do not carry a burden out of your houses on the sabbath or do any work, but keep the sabbath day holy, as I commanded your fathers.