One of the real problems I see in being Post-Trib is that means you are not allowed to read certain passages in the clear and plain way in which they are written, because they cause irreparable harm to the view if you do. The create conflicts which are not solvable from Scripture, and people end up saying things like, "It says
this, but it actually means
that", or, "this is a parable", though it not be in the form of a parable, such as the Sheep/Goats judgment.
Jesus gave that prophecy in the same narrative form as He did of His coming in power and glory a few minutes earlier. But when you think that Jesus is gathering the Church as part of "the chosen", then you have to ask youself, So, who exactly are these sheep in the next little bit? And if you try to put the church there, you have to ask, why are they being separated according to works? I thought Jesus knows those who are His!
I've not yet met a post tribber - that I can remember

- who accepts that passage exactly as written. Or the sealing of the 144,000. Or even Matthew 24:31, for that matter, as they import a meaning to "the chosen" that was not used in that day. Defining a word by it's usage by other people in other contexts decades later simply isn't accurate.
So to make "the chosen" and "the nations" anything other than Jews and Gentiles - in that day, among that people - is incorrect.
I've heard I don't know how many justifications for not just believing what we read, but that's the only way I find it all to harmonize.
In every case where I've watched the Spirit open my eyes to a passage, it's to see the full value of the words used, for the simplicity of what they say, and it's never, not once, to cause me to overturn the basic saying of a passage for something it metaphorically represents or some such, as these will always have Scripture instructing that very thing, "this is a type", like the parting of the Red Sea, or, this is allegory, Hagar is Jerusalem is the bondage of the Law, Sarah is the heavenly city, like that.
To have to somehow select without actual Biblical authority that this or that passage is actually type/parable/allegory, well, I certainly don't want to be in that position! I feel very much safer on the side of, well, that's what He said, so, I think it's what He meant.
Much love!