Good catch. We read right over so many statements, and our expectations color how and what we think of God's word.
Strong's Gr. 1551, "ἐκδέχομαι" - or, ekdechomai, defined as "to take or receive, by implication to wait for, expect"
The word is broken down in HELPS word studies as:
"1551 ekdéxomai (from 1537 /ek, "out from and to" and 1209/dexomai, "welcome") – properly, welcome from the heart, looking to the end-result of the waiting (literally, its "out-come," outcome)." (1)
An outcome, a result, an expected "end" for the until, or proper time to take action. Think of it as the probate of the will.
Death of the Testator
Time statements are very critical, and many students are not paying attention. Until we can take off the colored glasses that have been deliberately slipped over our eyes for the last 120 years or so, we cannot see. We have been blinded by a political agenda for a certain nation "state". (2)
"15 And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance.
6 For where a testament is, there must also of necessity be the death of the testator.
17 For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth." (Heb 9:15-17, KJV)
"For then must he often have suffered since the foundation of the world: but now once in the end of the world hath he appeared to put away sin by the sacrifice of himself." (Heb 9:26, KJV) or
"since it had behoved him many times to suffer from the foundation of the world, but now once, at the full end of the ages, for putting away of sin through his sacrifice, he hath been manifested;" (Heb 9:26, Young's)
The book of Hebrews was written about 60 - 65 AD, within 10 years of the destruction of the temple in AD 70. The author (probably Paul) stated that Christ Yeshua had been sacrificed "at the full end of the ages." Since time has continued on, and people are still born, still live their lives, and still die, then "the end of the ages" was not speaking of the end of time, nor the end of the physical cosmos.
Christ was manifested in "these last days" (1 Pet 1:20), and Christ was manifested and sacrificed in the 1st century AD, therefore "these last days" and "the end of the ages" refer to the first century AD when Christ came in the fullness of time (Gal. 4:4) to put an end to something.
Probate of the Will
After the death of the testator the will is read before the heirs.
From the time of His sacrifice on the cross (approx. 31 AD) to the time of the destruction of the temple (1st of Tishri, Sep AD 70- Note 3) was 40 years inclusively, and was the anti-type of the 40 years wandering in the wilderness after the exodus from Egypt. Forty (40) years = a generation. (4)
That 40 years of the new covenant was the time period during the first century AD when the gospel of Christ was broadcast, preached throughout the Roman empire (the world as defined by Luke 2:1 - Note 5).
"And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come." (Matt. 24:14, KJV)
"all the word" - was the Roman empire, the land they inhabited. During the probate period of the preaching of the word, the saints and assemblies were being prepared for "the end of days" that Gabriel had told Daniel to expect. That end of days was the end of the desolations of Jerusalem (Dan. 9:24-12:13). It was the end of the animal sacrificial worship system at that temple that had become profane once Christ was sacrificed on the cross.
A will has conditions that have to be met in order for the heirs to inherit.
"3 Blessed are the poor in spirit: for theirs is the kingdom of heaven.....5 Blessed are the meek: for they shall inherit the earth." (Matt. 5:3, 5, KJV)
Some commentators believe that Matt. 5:5 should go before Matt. 3:5, but Christ linked "the kingdom of heaven" with "inherit the earth." The phrase "inherit the earth" or land was a Hebrew idiom meaning great blessings. Though it referred to the old land promise of the Abrahamic covenant, Christ used it to refer to the kingdom of heaven. As such it did not mean a physical land nation / state, but the kingdom that came without observation (Luke 17:20) that is within the hearts of those who believe.
So, inheriting the earth was a synonym for the inheritance of the kingdom, the new promised land. And, the inheritance had to wait for probate of the will.
The End of Probate Period
"And white robes were given unto every one of them; and it was said unto them, that they should rest yet for a little season, until their fellowservants also and their brethren, that should be killed as they were, should be fulfilled." (Rev. 6:11, KJV)
How long is a short, or little season? 2,000+ years and counting?
Just as God sent His Son into the world at the fullness of time for his ministry (Gal. 4:4), God again sent His son at the last trump (the Feast of Trumpets, Yom Teruah) to take vengeance upon those who had crucified Him, and who were persecuting His saints.
The tribulation was to occur during this probate period (Matt. 24:6ff), and was the persecution of the saints under Nero who let all hell break loose against them, blaming the Christians for burning Rome (AD 64), and the short season the martyrs had to wait was during that last 6 years to the end of the siege for the destruction of Jerusalem and the temple by God's strong arm - the Roman army under Titus whose legion symbol was a lightning bolt (fire from heaven).
Christ was waiting at the right hand of the Father to come against Jerusalem to end the Mosaic covenant worship system, and to bring into full existence His everlasting kingdom.
That was the waiting expectation of Heb. 10:13. That was the probation period which ended with the judgment against Jerusalem that had been prophesied from Isaiah, Jeremiah, Ezekiel, Daniel, Haggai, Joel, etc.
The end of the desolations / destruction of Jerusalem was the "second" coming of Christ which had been promised to that same generation (Heb. 9:28) who had seen His first manifestation, and all the world (of the Roman empire) saw that desolation. That was the end of the probate period of the will.
The Inheritance - The Kingdom
He has not been waiting for 2,000+ years to take vengeance on "those who pierced Him" (Rev. 1:7). There are no "end of days" of an everlasting kingdom. The Messianic age took over legally at the cross of Christ, waited during the 40 years of the broadcast and probate of the will of the testator, and was fully and completely established 40 years later at the destruction of the temple in AD 70.
Those who are immersed in His name, are then anointed by the Holy Spirit as priests and kings in His kingdom (1 Pet. 2:9), and inherit the "earth" or promised land of the kingdom of heaven. All the saved / saints were waiting during that 40 years for that inheritance to be fully in effect. That is why all the letters to the churches/assemblies were constantly encouraging them to continue in their faith, to continue to believe, to be constant and patient.
The Everlasting Kingdom
The everlasting kingdom came in full force and effect at the end of the probate at the destruction of Jerusalem in AD 70. This was clearly outlined by the parable of the kingdom in Matt. 22:1-14. Destruction of the city, was the destruction of Jerusalem, at which time the feast of the bridegroom and marriage to the bride took place, and at that same feast, judgment began.
Christ finished one task, and started the next - the reign over the everlasting kingdom. He rules now, and has been ruling at the right hand of the Father since 70 AD. We have been living in the Messianic age, or the Christian age ever since.
Christ had told His disciples (Matt. 24 - 25) that when He returned He would come in judgement, with His kingdom, and would separate out those waiting in Hades at that time. That is when Daniel stood in his lot with the rest of those sheep Christ took home to heaven in AD 70. That is when Christ threw Hades into the lake of fire (Rev. 20:14) (6)
Christ has continued to judge both the nations, and the individual every single day since. We are living in His everlasting kingdom now - an everlasting kingdom which will never end.
Those early believers of the 1st century AD were the ones who were waiting. We don't have to wait for another coming, because Christ fulfilled all of those prophesies at His second coming in that generation, and He is already with us in His kingdom now. He rules and reigns now.
"to Him [is] the glory in the assembly in Christ Jesus, to all the generations of the age of the ages. Amen." (Eph. 3:21, Young's)
1) Strong's Gr. 1551 - biblehub
2) "It's Not The End of The World, Part VI -...." at ShreddingTheVeil
3) "The Signs of the Feasts - Part II...." at ShreddingTheVeil
4) "The Promised Land: Between the Cross and The Kingdom" at ShreddingTheVeil
5) "Frequent Mistakes - Part IV: Where Was All The World" at ShreddingTheVeil
6) "The Signs of Revelation - Part VI: Judgment Day..." at ShreddingTheVeil
(Bold emphasis is mine.)