I will match up Matthew 16:27-28 (and parallel) with the Olivet Discourse.
Matthew 16
[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] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.
Matthew 24
[30] And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.
Matthew 16
[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] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.
Matthew 24
[30] And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.
Matthew 16
[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] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.
Matthew 24
[31] And he shall send his angels with a great sound of a trumpet...
Timing is stated emphatically.Matthew 16
[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] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.
Matthew 24
[34] Verily I say unto you, This generation shall not pass, till all these things be fulfilled.
An equivalent prediction is given on the timing. There are different interpretations of Matthew 24:34, but on a "this first century generation" interpretation it fits perfectly with Matthew 16:28. There is a harmony between them.Matthew 16
[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] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.
Matthew 24
[34] Verily I say unto you, This generation shall not pass, till all these things be fulfilled.
Mark 9
And he said unto them, Verily I say unto you, That 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.
Matthew 24
[30] And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.
Luke 9
[26] For whosoever 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.
Luke 21
[31] So likewise ye, when ye see these things come to pass, know ye that the kingdom of God is nigh at hand.
Matthew 16
[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] Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.
Matthew 25
[31] When the Son of man shall come in his glory, and all the holy angels with him, then shall he sit upon the throne of his glory:
[32] And before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divideth his sheep from the goats...
Everything in those two verses (Matthew 16:27-28) can be matched up well with the Olivet Discourse.
Try matching up that material with the transfiguration. Try matching up that material with pentecost. (Or whatever other interpretation Christians will come up with.)
Some will say that verse 27 speaks of the "2nd coming", but that verse 28 speaks of something distinct.
If verse 27 is about the 2nd coming, and everything in verse 28 also fits with the 2nd coming/Olivet Discourse, then there is no good reason to say it has suddenly switched subject!