The Hebrew word sabbat describes the enjoyment of accomplishment, the celebration of completion. This is the rest we must enter into.
GEN 2:1 Thus the heavens and the earth were completed, and all their hosts.
GEN 2:2 And by the seventh day God completed His work which He had done; and He rested on the seventh day from all His work which He had done.
GEN 2:3 Then God blessed the seventh day and sanctified it, because in it He rested from all His work which God had created and made.
In GEN 2:2, creation was finished and on the seventh day God’s rest shows us that all has been planned and all has been done and that all will work out according to His good pleasure.
If we incorporate this same thinking into our own faith then we will also enter the same rest. It is a rest of maturity - a Sabbath rest.
The entire purpose of this letter to the Hebrews is to get these believers to enter the fulness of Promised Land rest.
HEB 4:1 Therefore, let us fear lest, while a promise remains of entering His rest, any one of you should seem to have come short of it.
HEB 4:2 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.
HEB 4:3 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.
HEB 4:4 For He has thus said somewhere concerning the seventh day, "And God rested on the seventh day from all His works";
HEB 4:5 and again in this passage, "They shall not enter My rest."
HEB 4:6 Since therefore it remains for some to enter it, and those who formerly had good news preached to them failed to enter because of disobedience,
HEB 4:7 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."
Psa 95 is quoted three times in this short passage. “Today” is emphasized (5 times). Do it now. “They shall not enter” is emphasized. Fear not entering. “Do not harden your hearts” is emphasized. Don’t be disobedient but rather believe.
HEB 4:8 For if Joshua had given them rest, He would not have spoken of another day after that.
Joshua had given them an earthly rest for part of a generation, but he could not give them or their children the Sabbath Rest of faith resulting in obedience.
Neither Joshua nor any great man of faith can give another person the rest of mature faith. The writer is refuting any belief that rest can come from being a part of great nations or having great leaders. This is actually a real problem in any society and is getting worse in our own. People look to the president or the leaders or the government for peace and prosperity when they only come from God. The leaders don’t refute the nonsense that they can make for happy people since that lie gets them elected. Jesus alone is the life that is the light of men.
Psa 95, three times quoted here, is written by David and another offer from God to Israel to enter into His rest (over 300 years after Joshua).
HEB 4:9 There remains therefore a Sabbath rest for the people of God.
Sabbath rest - sabbatismos = not the Sabbath day but rather the Sabbath observance or celebration.
HEB 4:10 For the one who has entered His rest has himself also rested from his works, as God did from His.
This is a part of the offer of God to mankind to enter into relationship with God in time. In time there are all kinds of opposition to that relationship; sin, persecution, deception, pride, lust, distraction, lies, ignorance, etc., but God has set the way of receiving that relationship and thus enter into His rest so that it can be enjoyed now.
Remember, the Sabbath is a day of rest and celebration. There are plenty of things in this world that make for solemn sorrow in the heart of the Christian, but that must not take over his heart. God has determined His good pleasure, and nothing happens in history outside of it. Men make terrible, deplorable decisions in sin and evil and hurt themselves and many others. Our sorrow for them must not take over our hearts. Sorrow is but for a moment whereas joy is forever.
HEB 12:1 Therefore, since we have so great a cloud of witnesses surrounding us, let us also lay aside every encumbrance, and the sin which so easily entangles us, and let us run with endurance the race that is set before us,
HEB 12:2 fixing our eyes on Jesus, the author and perfecter of faith, who for the joy set before Him endured the cross, despising the shame, and has sat down at the right hand of the throne of God.
who instead of (preposition anti) the joy then present with Him endured the Cross, [K. Wuest]
The Lord laid aside His joy when He endured the cross, and at times, in picking up our cross, we also lay aside our joy, but this is only for a time. We are not to go through life joyless, in fact quite the opposite.
MAT 5:11 “Blessed are you when men cast insults at you, and persecute you, and say all kinds of evil against you falsely, on account of Me.
MAT 5:12 Rejoice, and be glad, for your reward in heaven is great, for so they persecuted the prophets who were before you.”