Q. Does the Bible teach we should observe the Sabbath? If not,what is the meaning of the fourth chapter of Hebrews?
The observance of the Sabbath was part of the Old Covenant. The Old Covenant was nailed to the cross, and done away with.
1* Therefore, let us fear if, while a promise remains of entering His rest, any one of you may seem to have come short of it.
2* For indeed we have had good news preached to us, just as they also; but the word they heard did not profit them, because it was not united by faith in those who heard.
3* For we who have believed enter that rest, just as He has said, "AS I SWORE IN MY WRATH, THEY SHALL NOT ENTER MY REST," although His works were finished from the foundation of the world.
4* For He has said somewhere concerning the seventh day: "AND GOD RESTED ON THE SEVENTH DAY FROM ALL HIS WORKS";
5* and again in this passage, "THEY SHALL NOT ENTER MY REST."
6* Therefore, since it remains for some to enter it, and those who formerly had good news preached to them failed to enter because of disobedience,
7* He again fixes a certain day, "Today," saying through David after so long a time just as has been said before, "TODAY IF YOU HEAR HIS VOICE, DO NOT HARDEN YOUR HEARTS."
8* For if Joshua had given them rest, He would not have spoken of another day after that.
9* So there remains a Sabbath rest for the people of God.
10* For the one who has entered His rest has himself also rested from his works, as God did from His.
2) Hebrews 4 does not teach the Sabbath today. The "Sabbath rest" of verse 8 is a reference to Heaven. We must be obedient to God, unlike the children of Israel who disobeyed God and died in the wilderness, in order to enter into God's "Sabbath rest" (Heaven).
The "one who has entered His rest" is Jesus Christ, who now reigns in Heaven on the throne of David (Acts 2:30-36).