You're not reading very closely. Jesus is not only talking to those disciples with him at that time, but also their lawful successors. For Jesus says He will be with them until the consummation of the world. The disciples with Him at that time obviously were not to remain on earth until the consummation of the world. Therefore you err. Again.
And Jesus coming, spoke to them, saying: All power is given to me in heaven and in earth. [19] Going therefore, teach ye all nations; baptizing them in the name of the Father, and of the Son, and of the Holy Ghost. [20] Teaching them to observe all things whatsoever I have commanded you: and behold I am with you all days, even to the consummation of the world. (Mat. 28:18-20).
Nope.
He had also said this to them - much earlier...
Matthew 10:21 And the brother shall deliver up the brother to death, and the father the child: and the children shall rise up against their parents, and cause them to be put to death. 10:22 And ye shall be hated of all men for my name's sake: but he that endureth to the end shall be saved. 10:23 But when they persecute you in this city, flee ye into another: for verily I say unto you, Ye shall not have gone over the cities of Israel, till the Son of man be come.
And that began to play out - in Acts 4-8.
Which was why Stephen saw the Lord no longer sitting at the Father's right hand in Acts 7.
Here, He was depicted as sitting...until.
Acts 2:32 This Jesus hath God raised up, whereof we all are witnesses. 2:33 Therefore being by the right hand of God exalted, and having received of the Father the promise of the Holy Ghost, he hath shed forth this, which ye now see and hear. 2:34 For David is not ascended into the heavens: but he saith himself, The Lord said unto my Lord, Sit thou on my right hand, 2:35 Until I make thy foes thy footstool. 2:36 Therefore let all the house of Israel know assuredly, that God hath made that same Jesus, whom ye have crucified, both Lord and Christ.
Here, He is depicted as standing...
Acts 7:51 Ye stiffnecked and uncircumcised in heart and ears, ye do always resist the Holy Ghost: as your fathers did, so do ye. 7:52 Which of the prophets have not your fathers persecuted? and they have slain them which shewed before of the coming of the Just One; of whom ye have been now the betrayers and murderers: 7:53 Who have received the law by the disposition of angels, and have not kept it. 7:54 When they heard these things, they were cut to the heart, and they gnashed on him with their teeth. 7:55 But he, being full of the Holy Ghost, looked up stedfastly into heaven, and saw the glory of God, and Jesus standing on the right hand of God, 7:56 And said, Behold, I see the heavens opened, and the Son of man standing on the right hand of God. 7:57 Then they cried out with a loud voice, and stopped their ears, and ran upon him with one accord, 7:58 And cast him out of the city, and stoned him: and the witnesses laid down their clothes at a young man's feet, whose name was Saul. 7:59 And they stoned Stephen, calling upon God, and saying, Lord Jesus, receive my spirit. 7:60 And he kneeled down, and cried with a loud voice, Lord, lay not this sin to their charge. And when he had said this, he fell asleep.
Why that prayer?
Because as that cool old Native American in the great Clint Eastwood Western classic "The Outlaw Josey Wales" says, when he sees Josey off in the distance coming to rescue them from them Comancheros - "Get ready, granny; hell's comin tuh breakfast..."
In other words, the world was then headed for hell on Earth, there, In Acts 7, thus, Stephen's prayer for his nation...
Isaiah 28:16 Therefore thus saith the Lord GOD, Behold, I lay in Zion for a foundation a stone, a tried stone, a precious corner stone, a sure foundation: he that believeth shall not make haste. 28:17 Judgment also will I lay to the line, and righteousness to the plummet: and the hail shall sweep away the refuge of lies, and the waters shall overflow the hiding place. 28:18 And your covenant with death shall be disannulled, and your agreement with hell shall not stand; when the overflowing scourge shall pass through, then ye shall be trodden down by it. 28:19 From the time that it goeth forth it shall take you: for morning by morning shall it pass over, by day and by night: and it shall be a vexation only to understand the report. 28:20 For the bed is shorter than that a man can stretch himself on it: and the covering narrower than that he can wrap himself in it. 28:21 For the LORD shall rise up as in mount Perazim, he shall be wroth as in the valley of Gibeon, that he may do his work, his strange work; and bring to pass his act, his strange act. 28:22 Now therefore be ye not mockers, lest your bands be made strong: for I have heard from the Lord GOD of hosts a consumption, even determined upon the whole earth.
Malachi 4:1 For, behold, the day cometh, that shall burn as an oven; and all the proud, yea, and all that do wickedly, shall be stubble: and the day that cometh shall burn them up, saith the LORD of hosts, that it shall leave them neither root nor branch. 4:2 But unto you that fear my name shall the Sun of righteousness arise with healing in his wings; and ye shall go forth, and grow up as calves of the stall. 4:3 And ye shall tread down the wicked; for they shall be ashes under the soles of your feet in the day that I shall do this, saith the LORD of hosts. 4:4 Remember ye the law of Moses my servant, which I commanded unto him in Horeb for all Israel, with the statutes and judgments. 4:5 Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the LORD: 4:6 And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.
But what happened, instead?
What happened is what God planned to temporarily interrupt that with...
Romans 9:19 Thou wilt say then unto me, Why doth he yet find fault? For who hath resisted his will?
In other words, the unbelieving Israelites response is "what's the hold up now; why doesn't He pour His wrath already, and get it over with?"
Reply?
Romans 9:20 Nay but, O man, who art thou that repliest against God? Shall the thing formed say to him that formed it, Why hast thou made me thus?
Remember, Israelite, what His reply was one of those others times you took issue with His delay of His wrath; remember what He said back then?
Romans 9:21 Hath not the potter power over the clay, of the same lump to make one vessel unto honour, and another unto dishonour?
Well, such is the case, this time around also...
Romans 9:22 What if God, willing to shew his wrath, and to make his power known, endured with much longsuffering the vessels of wrath fitted to destruction: 9:23 And that he might make known the riches of his glory on the vessels of mercy, which he had afore prepared unto glory, 9:24 Even us, whom he hath called, not of the Jews only, but also of the Gentiles?
Nevertheless, His hell is yet comin to breakfast, Israel...prior to His also Prophesied goodness unto Abraham, Isaac, and Jacob, and their Multiplied "sons of Jacob" at last......
Romans 9:28 For he will finish the work, and cut it short in righteousness: because a short work will the Lord make upon the earth. 9:29 And as Esaias said before, Except the Lord of Sabaoth had left us a seed, we had been as Sodoma, and been made like unto Gomorrha.
Acts 17:11,12