These three answers are similar to what I always believed as well, but I'm now questioning that interpretation. I'm not fully in agreement with Logabe on the rest of his answer, but now that I've been looking at the passage in a new light, the 1,000 year reign of Christ on earth makes a strong case for being the "rest" they were laboring to enter into, with the millennium being the "Sabbath" or 7th "day" of creation in keeping with 2 Peter 3:8 (and yes, Dave. I know you would not agree with that position at all, LoL).
But let me post the passage, starting with Chapter 3:
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1 Therefore, holy brethren, partakers of the heavenly calling, consider the Apostle and High Priest of our confession, Christ Jesus, 2 who was faithful to Him who appointed Him, as Moses also was faithful in all His house. 3 For this One has been counted worthy of more glory than Moses, inasmuch as He who built the house has more honor than the house. 4 For every house is built by someone, but He who built all things is God. 5 And Moses indeed was faithful in all His house as a servant, for a testimony of those things which would be spoken afterward, 6 but Christ as a Son over His own house, whose house we are if we hold fast the confidence and the rejoicing of the hope firm to the end.
7 Therefore, as the Holy Spirit says:
“Today, if you will hear His voice,
8 Do not harden your hearts as in the rebellion,
In the day of trial in the wilderness,
9 Where your fathers tested Me, tried Me,
And saw My works forty years.
10 Therefore I was angry with that generation,
And said, ‘They always go astray in their heart,
And they have not known My ways.’
11 So I swore in My wrath,
‘They shall not enter My rest.’ ”
12 Beware, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God; 13 but exhort one another daily, while it is called “Today,” lest any of you be hardened through the deceitfulness of sin. 14 For we have become partakers of Christ if we hold the beginning of our confidence steadfast to the end, 15 while it is said:
“Today, if you will hear His voice,
Do not harden your hearts as in the rebellion.”
16 For who, having heard, rebelled? Indeed, was it not all who came out of Egypt, led by Moses? 17 Now with whom was He angry forty years? Was it not with those who sinned, whose corpses fell in the wilderness? 18 And to whom did He swear that they would not enter His rest, but to those who did not obey? 19 So we see that they could not enter in because of unbelief.
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Now. Here he states that the "rest" the Israelites "could not enter into" in v.16-19 was the promised land. If you look at the other New Testament writings, the spiritual promised land was something the New Testament saints had NOT entered into yet. Look at 1 Corinthians 19, where Paul talked about the same subject matter:
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1 Moreover, brethren, I do not want you to be unaware that all our fathers were under the cloud, all passed through the sea, 2 all were baptized into Moses in the cloud and in the sea, 3 all ate the same spiritual food, 4 and all drank the same spiritual drink. For they drank of that spiritual Rock that followed them, and that Rock was Christ. 5 But with most of them God was not well pleased, for their bodies were scattered in the wilderness.
6 Now these things became our examples, to the intent that we should not lust after evil things as they also lusted. 7 And do not become idolaters as were some of them. As it is written, “The people sat down to eat and drink, and rose up to play.” 8 Nor let us commit sexual immorality, as some of them did, and in one day twenty-three thousand fell; 9 nor let us tempt Christ, as some of them also tempted, and were destroyed by serpents; 10 nor complain, as some of them also complained, and were destroyed by the destroyer. 11 Now all these things happened to them as examples, and they were written for our admonition, upon whom the ends of the ages have come. 12 Therefore let him who thinks he stands take heed lest he fall.
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The phrase "upon whom the ends of the ages" points to the promised that they were seeking, but they had not attained it yet. All of his examples of the Israelites "falling" here are taken from the forty years in the wilderness, BEFORE they entered the promised land. The Israelites were eating and drinking of Christ, but had not yet entered the promised land, and likewise the New Testament saints were eating and drinking of Christ but needed to be careful lest they likewise fall before reaching the promised land themselves.
So you combine the two passages and you get, A. The "rest" of God was the "promised land," and B. They had not attained to that "promised land" yet during New Testament times.
Now skipping ahead to verse 11 of Hebrews, Chapter 4:
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11 Let us therefore be diligent to enter that rest, lest anyone fall according to the same example of disobedience. 12 For the word of God is living and powerful, and sharper than any two-edged sword, piercing even to the division of soul and spirit, and of joints and marrow, and is a discerner of the thoughts and intents of the heart. 13 And there is no creature hidden from His sight, but all things are naked and open to the eyes of Him to whom we must give account.
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Again we have the New Testament saints being compared to those who fell in the wilderness BEFORE reaching the promised land. Just as the Israelites fell by the sword, so too would the NT saints fall by the sword of God (i.e. His word) if they continued to live in persistent sin (see 1 Corinthians 11:29-34; 1 Corinthians 5:1-5; Revelations 2:22-23).
Any comments? It seems fairly cut and dried to me that the rest of the promised land must parallel the rest of Christ's millennial reign, the 7th "day" or thousand years when Christ will finally rest from His work of bringing forth a harvest from the earth.