Exodus 20:11
8 “ Remember the Sabbath day, to keep it holy. 9 Six days you shall labor and do all your work, 10 but the seventh day is the Sabbath of the LORD your God. In it you shall do no work: you, nor your son, nor your daughter, nor your male servant, nor your female servant, nor your cattle, nor your stranger who is within your gates. 11 For in six days the LORD made the heavens and the earth, the sea, and all that is in them, and rested the seventh day. Therefore the LORD blessed the Sabbath day and hallowed it.
As you said, Jesus said that he is the Lord of the Sabbath. In Mark 2:27, He said, "Then he said to them, “The Sabbath was made for man, not man for the Sabbath." God "created" the Sabbath because He knew that man would eventually get so busy working and trying to make money that they would not make time for the Lord OR for resting. When He "worked" for six days creating the world, He then rested on the seventh to set a pattern for taking time to rest. Jews traditionally observe Sabbath from what we call sundown on Friday until sundown on Saturday. The Pharisees had turned the simple commandment that God had given into a list of things that were considered "work". I found this list...
1. Sowing
2. Plowing
3. Reaping
4. Binding sheaves
5. Threshing
6. Winnowing
7. Selecting
8. Grinding
9. Sifting
10. Kneading
11. Baking
12. Shearing wool
13. Washing wool
14. Beating wool
15. Dyeing wool
16. Spinning
17. Weaving
18. Making two loops
19. Weaving two threads
20. Separating two threads
21. Tying
22. Untying
23. Sewing two stitches
24. Tearing
25. Trapping
26. Slaughtering
27. Flaying
28. Salting meat
29. Curing hide
30. Scraping hide
31. Cutting hide up
32. Writing two letters
33. Erasing two letters
34. Building
35. Tearing a building down
36. Extinguishing a fire
37. Kindling a fire
38. Hitting with a hammer
39. Taking an object from the private domain to the public, or transporting an object in the public domain.
Although it was enacted by rabbis before our times, you can add things for today's life. Turning on a light switch is a violation of #37. So, is turning on a stove. So, very "devout" Jews will prepare their meals the day before the Sabbath to be eaten cold so that they wouldn't have to heat it up.
Since the beginning of the church, Christians have observed their day of rest as the Lord's Day (Sunday) commemorating the day of the Lord's resurrection, although not all do. In today's culture with work schedules, it's not always possible to observe either the Saturday or a Sunday day of rest. In that case, a person could decide what their day of rest and worship should be. The Sabbath was made for man, not man for the Sabbath.