John actually.
Children, it is the last hour; and just as you heard that Antichrist is coming, even now many antichrists have appeared; from this we know that it is the last hour.
—1 John 2:18
It was Jesus who said this generation would not pass away before the the Second Coming.
Mt 24
The Coming of the Son of Man
29 “Immediately after the tribulation of those days the sun will be darkened, and the moon will not give its light, and the stars will fall from heaven, and the powers of the heavens will be shaken; 30 then will appear the sign of the Son of man in heaven, and then all the tribes of the earth will mourn, and they will see the Son of man coming on the clouds of heaven with power and great glory; 31 and he will send out his angels with a loud trumpet call, and they will gather his elect from the four winds, from one end of heaven to the other.
The Lesson of the Fig Tree
32 “From the fig tree learn its lesson: as soon as its branch becomes tender and puts forth its leaves, you know that summer is near. 33 So also, when you see all these things, you know that he is near, at the very gates. 34 Truly, I say to you, this generation will not pass away till all these things take place.
Red Matt 24 and Mark 13, then read Luke 21. A careful reading will discover that Luke has Jesus saying ‘but before these things, while Matthew and Mark have Jesus saying THEN. Also, the Olivet discourse is found in Mark and Matthew as a private discourse by Jesus to Peter, James, John, and Andrew, on the mount of Olives. While Luke’s passage in Luke 21 is Jeus speaking to ‘his followers’ in the Temple. This should clue you in that there is not only a subtle difference in audeince but the message to each of the audiences. It happens that the discourse given by Jesus in the Temple, given to us by Luke, gave the listeners enough clues to escape Jersualem when the Roman armies paused outside of Jerusalem for nine months while Vespasian wen tback to Rome. The disciples had a better handle on the teachings afterThe Holy Spirit came at Pentecost.