Your confused becasue you accepted a teaching called the "second coming" long befroe you became familiar enough with the scripture to see that the "coming of the Lord" has happened on multiple occasions throughout the OT. It is not a NT doctrine. It is an OT doctrine and an OT experience. Now that the coming of the Lord, which are great days of judgment and calamity that the Lord physically comes down to earth to oversee continues they always have. Your confused. Confused that is, that Jesus would say to whom and when he was coming. (Just like he did in the OT.)
The only difference between his coming in the OT in great days of judgment and to fulfill promise is: IN the OT he physically came to earth as Jehovah the Word. Today he comes as the descendant of Abraham, the messiah. The son of David etc etc. He was not those things until he left heaven and became a man.
Jesus told many of the people he was speaking to, including the apostle John, that they would live long enough to see the coming of the Lord? Here Matthew, Mark and Luke all record the same scene when Jesus tells a group of his disciples that some of them will live long enough to see his coming.
Matthew16: 27. For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works. 28: TRULY I SAY TO YOU. THERE ARE SOME STANDING HERE, WHICH SHALL NOT TASTE OF DEATH, TILL THEY SEE THE SON OF MAN COMING IN HIS KINGDOM.
Mark 8:38 Whoever therefore shall be ashamed of me and of my words in this adulterous and sinful generation; of him also shall the Son of man be ashamed, when he comes in the glory of his Father with the holy angels. 9:1 And he said to them. TRULY i SAY TO YOU. THERE BE SOME OF THEM THAT STAND HERE, WHICH SHALL NOT TASTE OF DEATH, TILL THEY HAVE SEEN THE KINGDOM OF GOD COME WITH POWER.
Luke 9:26 For whoever shall be ashamed of me and of my words, of him shall the Son of man be ashamed, when he shall come in his own glory, and in his Father's, and of the holy angels. 27 BUT I TELL YOU OF A TRUTH. THERE BE SOME STANDING HERE, WHICH SHALL NOT TASTE OF DEATH, TILL THEY SEE THE KINGDOM OF GOD.
Here Jesus tells John that he will live long enough to see his coming but tells Peter he will not.
John 21:18. (Jesus speaking to Peter) Truly, Truly, I say to you, When you were young, you dressed yourself, and walked where ever you desired: but when your old, you will stretch forth your hands, and another will dress you, and carry you where you do not want. 19. This he spoke, signifying by what death he (Peter) should glorify God. And when he had spoken this, he said to him, Follow me. 20. Then Peter, turning around, seeing the disciple whom Jesus loved (John) following...... 21. Peter seeing him said to Jesus, Lord, and what shall this man do? 22. Jesus answers him, IF I WILL THAT HE REMAIN TILL I COME, what is that to you? Follow me. 23. Then this saying abroad went out among the brothers, that this disciple (John) should not die: yet Jesus did not say to him, He shall not die; BUT IF I WILL THAT HE REMAIN TILL I COME, what is that to you?
Then Jesus tells the High Priest and the other religious leaders of Israel that some of them would live long enough to see his coming.
Mark 14:61 ...Again the high priest asked him, Are you the Christ, the Son of the Blessed? 62. And Jesus said, I am: AND YOU WILL SEE THE SON OF MAN SITTING ON THE RIGHT HAND OF POWER AND COMING IN THE CLOUDS OF HEAVEN.
Then of course there is Jesus's prophecy about the destruction of the temple and the city of Jerusalem. It is very important to note that the only place in his whole prophecy that he used the emphasis "truly truly I say to you;" to command their attention, and ours, was concerning when this prophecy would come to pass.
Matthew 24:32. Now learn a parable of the fig tree; When his branch is yet tender, and puts forth leaves, you know that summer is close: 33. So likewise, when you shall see all these things, know that it is near, even at the doors. 34, IN TRUTH IS SAY TO YOU, THIS GENERATION SHALL NOT PASS, TILL ALL THESE THINGS BE FULFILLED. 35. Heaven and earth shall pass away, but my words shall not pass away. 36. But of that day and hour knows no man, no, not the angels of heaven, but my Father only.
Mark 13:28. Now learn a parable of the fig tree; When her branch is yet tender, and puts forth leaves, you know that summer is near: 29. So in like manner, when you shall see these things come to pass, know that it is close, even at the doors. 30. IN TRUTH I SAY TO YOU, THAT THIS GENERATION SHALL NOT PASS, TILL ALL THESE THINGS BE DONE. 31. Heaven and earth shall pass away: but my words shall not pass away. 32. But of that day and that hour knows no man, no, not the angels which are in heaven, neither the Son, but the Father.
Luke 21:29. And he spoke to them a parable; Behold the fig tree, and all the trees; 30. When they now shoot forth, you see and know of your own selves that summer is now close at hand. 31. So likewise ye, when ye see these things come to pass, know that the kingdom of God is close at hand. 32. IN TRUTH I SAY TO YOU. THIS GENERATION SHALL NOT PASS AWAY, TILL ALL BE FULFILLED. 33. Heaven and earth shall pass away: but my words shall not pass away.
This is all in exact accordance with Daniels prophecy that when the messiah comes the city and the sanctuary would be destroyed. In fact the destruction of the temple and the city was one of the major signs that Jesus was indeed the messiah. Just like his death and resurrection were.
Daniel chapter 9 verses 25-27. Know therefore and understand, that from the going forth of the commandment to restore and to build Jerusalem unto the Messiah the Prince shall be seven weeks, and threescore and two weeks: the street shall be built again, and the wall, even in troublous times. And after threescore and two weeks shall Messiah be cut off, but not for himself: AND THE PEOPLE OF THE PRINCE THAT SHALL COME SHALL DESTROY THE CITY AND THE SANCTUARY, and the end thereof shall be with a flood, and unto the end of the war desolation's are determined. And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate.
So why do so many Christians and pastors not pay any attention to all these scriptures that say when Jesus would come and instead place it in our future? Mostly because they have no incentive to notice them. They accepted a teaching called the "second coming" as gospel long before they became familiar enough with the scripture to observe anything contrary to it. In the Greek, the phrase second coming doesn't even occur one time in the entire New Testament. The acceptance of these pop culture end time teachings has quite naturally caused a spiritual and intellectual laziness around the subject of the coming of the Lord. Yet the scripture is replete with these great days of judgment where the Lord literally and physically came to earth to oversee great days of judgment or calamity. This isn't the only one the New Testament prophesied either. There are a dozen chapters of end time prophecy about the great judgments of the end of the age of the four Gentile empires in the OT and book of Revelation.
Every single sentence of Jesus's prophecy in Matthew 24, Mark 13, and Luke 21 came to pass in the first century. You'll not find a more complete account in a more easy to read format like the article linked below. Please take the time to read it. There is extremely good news about our future, not apocalyptic news.
http://wordservice.org/Bible%20Basics/bb3000.htm