Q: Isn’t it a false prophecy in Matthew 16:28 when Jesus said that some of His disciples would see Him in His kingdom before they died, since the second coming didn’t end up happening in their lifetimes?
A: It was an accurate prophecy that was fulfilled seven days later through the transfiguration, when Peter, James, and John were blessed by getting to see a preview of Christ in His kingdom (which didn’t manifest in earthly form, because His people rejected Him as king) and glory (which He had laid down in order to be a servant during His earthly mission). We know that Jesus was not prophesying that His second coming for the purpose of judgment would happen before the disciples died, because He already said that as a man, He didn’t know when that was going to happen (Matt 24:36).
To get a bit of context for the verse of concern, consider the verse just previous to it:
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. ~ Matt 16:27
Here, Jesus is clearly talking about the end-of-time judgment when everyone shall see Him in His glory.
To understand what it looks like for Christ to be in His glory, we will consider the following scriptural passages, from both the Old and New Testaments:
9 I beheld till the thrones were cast down, and the Ancient of days did sit, whose garment was white as snow, and the hair of his head like the pure wool: his throne was like the fiery flame, and his wheels as burning fire.
10 A fiery stream issued and came forth from before him: thousand thousands ministered unto him, and ten thousand times ten thousand stood before him: the judgment was set, and the books were opened. ~ Daniel 7:9-10
27 And I saw as the colour of amber, as the appearance of fire round about within it, from the appearance of his loins even upward, and from the appearance of his loins even downward, I saw as it were the appearance of fire, and it had brightness round about.
28 As the appearance of the bow that is in the cloud in the day of rain, so was the appearance of the brightness round about. This was the appearance of the likeness of the glory of the LORD. ~ Ezekiel 1:27-28
13 And in the midst of the seven candlesticks one like unto the Son of man, clothed with a garment down to the foot, and girt about the paps with a golden girdle.
14 His head and his hairs were white like wool, as white as snow; and his eyes were as a flame of fire;
15 And his feet like unto fine brass, as if they burned in a furnace; and his voice as the sound of many waters. ~ Revelation 1:13-15
And unto the angel of the church in Thyatira write; These things saith the Son of God, who hath his eyes like unto a flame of fire, and his feet are like fine brass; ~ Rev 2:18
So these are pictures of the Lord in glory here. They include the following features: brass-coloured skin, white woolen hair, royal garments, flames issuing from Him, and brightness enveloping Him.
Now let us consider the verse of concern, the very next verse in Matthew:
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. ~ Matt 16:28
So, first He makes a parallel between the nouns glory and kingdom. In verse 27, He announces that at the second coming He’ll come in glory with an agenda of judgment for everyone. Then in verse 28, He adds that some of those listening will get a preview of Him in the glory of His kingdom within their lifetimes. Again, the emphasis is that we are all going to see Him in His glory at the judgment (vs 27); but a few will get that honour in advance (vs 28). And that happens for Peter, James, and John, as described in the very next chapter, via the transfiguration.
1 And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an high mountain apart,
2 And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light. ~ Matt 17:1-2
Here we see again the same image of fiery radiance as described in the prior passages.
John later testifies to this experience and its significance in John 1:14, in which he says:
And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth. ~ John 1:14
When John says they beheld Jesus’ glory, he is not talking about the regular flesh and blood Jesus that everyone saw. That was not Jesus in His glory; that was Him appearing as a regular, nondescript Jewish man. The glory viewing occurred during the transfiguration, and only those three were privy to it.
Another clue that we are seeing a preview of Jesus in His future kingdom in the transfiguration is the presence of Moses and Elijah there. From the same passage in Matthew:
And, behold, there appeared unto them Moses and Elias talking with him [Jesus]. ~ Matt 17:3
Moses and Elijah are going to be part of Christ’s future kingdom, just as are all the saints.
When Jesus made that statement, He was prophesying that in short order, a trio of His disciples would be blessed with a preview of Him in His glory and kingdom, giving those three that image to hold onto through the severe trials that were to come, just as God had done with other of his servants including Daniel, Isaiah, Ezekiel, and Moses.