Here again Paul addresses it in Romans,
13 For
the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith.
14 For if they which are of the law be heirs, faith is made void, and the promise made of none effect: (Rom 4:13-14 KJV)
The promise of the Land comes through faith. And again,
16 The Spirit itself beareth witness with our spirit, that we are the children of God:
17 And
if children, then heirs; heirs of God, and
joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together. (Rom 8:16-17 KJV)
what is Christ's inheritance?
6 Yet have I set my king upon my holy hill of Zion.
7 I will declare the decree: the LORD hath said unto me, Thou art my Son; this day have I begotten thee.
8 Ask of me, and
I shall give thee the heathen for thine inheritance, and the uttermost parts of the earth for thy possession.
(Psa 2:6-8 KJV)
The word "earth" here is literally, the land.
Salvation is being resurrected receiving the inheritance which is the land Promised to Abraham. The Israelites going into the Promised Land was was a conditional inheritance, if the kept the Law they could stay in the Land, if they didn't they would be kicked and we see they were. So Paul using the Israelites as an example of entering or not entering the Promised land and equating it with the future entrance into the Promised land is most certainly referring to salvation. When Paul speaks of "we who believe do enter that rest" he is speaking of the believer entering the Promised land which is salvation.
Now, you can say this one or that one did or didn't enter in, however, Paul makes it abundantly clear that there was a group in wilderness the did not enter that future rest.
KJV Hebrews 4:1 Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it.
2 For unto us was the gospel preached, as well as unto them: but the word preached did not profit them, not being mixed with faith in them that heard it. {the word...: Gr. the word of hearing} {not being...: or, because they were not united by faith to}
3
For we which have believed do enter into rest, as he said, As I have sworn in my wrath, if they shall enter into my rest: although the works were finished from the foundation of the world.
4 For he spake in a certain place of the seventh day on this wise, And God did rest the seventh day from all his works.
5 And in this place again, If they shall enter into my rest.
6 Seeing
therefore it remaineth that some must enter therein,
and they to whom it was first preached entered not in because of unbelief: {it was: or, the gospel was}
7 Again, he limiteth a certain day, saying in David, To day, after so long a time; as it is said, To day if ye will hear his voice, harden not your hearts.
8 For if Jesus had given them rest, then would he not afterward have spoken of another day. {Jesus: that is, Joshua}
9 There remaineth therefore a rest to the people of God. {rest: or, keeping of a sabbath}
10 For he that is entered into his rest, he also hath ceased from his own works, as God did from his.
11 Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief. (Heb 4:1-11 KJV)
There is the future rest and he said some from the wilderness did not enter into it.
So, I'm not missing the point about the Jews physical entrance into the land. I think what many miss is that the picture of the Jews entrance into the promised land, is a picture of salvation. Just as the Jews were promised rest upon entering the land, the believer is promised rest upon entering the land.
Also, since you've brought up Moses and Aaron, Paul specifies that it was some, not all who rebelled.
15 While it is said, To day if ye will hear his voice, harden not your hearts,
as in the provocation.
16
For some, when they had heard,
did provoke: howbeit
not all that came out of Egypt by Moses.
17 But
with whom was he grieved forty years? was it not with them that had sinned,
whose carcases fell in the wilderness? (Heb 3:15-17 KJV)
Tell me what this Gospel that was preached to the Israelite in the wilderness ? Yes Paul tells us there is a rest which isn't the one that Joshua et al entered when they crossed the Jordan.
It's what I explained above. For a more detailed explanation with a lot more Scriptural references you can look my article,
"The Kingdom of God (A Biblical Perspective)"