Matthew 16:28. & Luke 9:27
Either Jesus cannot tell the literal truth from an allegorical claim, OR He is a liar. You choose!
Matt 16:28 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.
It is always revealing, how we say that some Bible verses are to be taken literally and others are to be taken allegorically; revealing be cause while some Bible passages are considered allegorical by their very content and context, others are described as allegorical to suit the pre-existing theology of those describing them as such. 
A good example of the former is where Jesus wept over Jerusalem, saying,”how often would I have gathered thy children together, even as a hen gathereth her chickens under her wings.”. Are we to presume therefore that Jesus or God are a cosmic chicken? I think not. A good example of the latter are these passages mentioned above.
They read, “Matt 16:24-28 (KJVA) Then said Jesus unto his disciples, If any man will come after me, let him deny himself, and take up his cross, and follow me. 25 For whosoever will save his life shall lose it: and whosoever will lose his life for my sake shall find it. 26 For what is a man profited, if he shall gain the whole world, and lose his own soul? or what shall a man give in exchange for his soul? 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.
And…
Luke 9:23-27 (KJVA) And he said to them all, If any man will come after me, let him deny himself, and take up his cross daily, and follow me. 24 For whosoever will save his life shall lose it: but whosoever will lose his life for my sake, the same shall save it. 25 For what is a man advantaged, if he gain the whole world, and lose himself, or be cast away? 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.
Now here is a truly amazing thing.
Do you know even ONE SINGLE sect, schism or denomination that dismisses as allegorical ANYTHING in the context – ANYTHING???
If any man will come after me, let him deny himself, and take up his cross, and follow me? Literal? Oh Yes!!
“For what is a man profited, if he shall gain the whole world, and lose his own soul? or what shall a man give in exchange for his soul?” Literal? Oh Yes!!
Now by contrast, what does Christianity do with the ONLY verse prefaced by Jesus saying, “Verily”, Of a truth”, “I tell you truthfully”
In ALL the other content, uttered by Jesus, it is all actual, but in the only verse which Jesus emphasizes with the words, “I tell you truthfully”, we cannot accept the truth and so we call it allegorical, futuristic, anything BUT simple straightforward truth!
How amusing!
Jesus said,
Luke 9:27 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.
Matthew 16:28 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.
Either Jesus cannot tell the difference between the present and the future, OR He is a liar. 
You choose!
Jesus has already come the second time, without sin unto salvation. Hebrews 9:28