Luke 21:33 Heaven and earth shall pass away: but my words shall not pass away.
The sky and the planet are going to pass by, my ideas however, are never going to pass by.
This verse is the same as that in Mark 13:31 but both are slightly different than Matthew 24:35 where the last "pass away" is only a possibility. However, the big surprise here is that the Greek word translated as "pass away" doesn't mean what the English phrase means.
The word translated as "heaven" means sky, the climate, and the universe. It also meant the home of the gods in a physical sense: the sun, moon, and planets were named for the gods. More about the word in this article.
The word translated as "earth" means the physical planet, not society, which Christ describes as the world. See this article for more on these words.
The phrase "pass away" is from a verb that means "go by", "pass by", "outstrip" (in speed), and "pass over". The form is the future tense. The sense here could be "pass by", "surpass", but the sense of "pass away" as in "die" is not at all clear. The word means to pass the time and can refer to times past, but it also means to "outwit" and "elude" and "be superior". It also means to "pass by" a place or to "arrive" at a place. In the Latin Vulgate, this verb was translated as transient which is the future, plural, active form of the transit, which means "to cross". In Greek, the form is neither active nor passive, but the middle form which means that the subjects are acting on themselves.
"Words" is translated from a Greek word that means "calculation," or "reasoning." It is the source of our word "logic" and is the root word for all the English words that end in "-ology." Most biblical translations translated it as "word" for somewhat poetic reasons. More about this word in this article.
The "not" here is both of the Greek negatives used together. Greek has two negatives, one objective, one subjective. The use of both together is more extreme, like saying "you cannot really think" or, more simply, "never".
The phrase "pass away" is from same verb as above that means "go by", "pass by", "outstrip" (in speed), and "pass over". The form is the same as the word above as well.
ὸ οὐρανὸς (noun pl masc nom) "Of Heaven" is from the Greek ouranos, which means "heaven as in the vault of the sky", "heaven as the seat of the gods", "the sky", "the universe," and "the climate."
καὶ (conj/adv) "And" is from kai, which is the conjunction joining phrases and clauses, "and," or "but." After words implying sameness, "as" (the same opinion as you). Used in series, joins positive with negative "Not only...but also." Also used to give emphasis, "even", "also," and "just."
ἡ γῆ (noun sg fem nom) "Earth" is from ge, which means "the element of earth", "land (country)", "arable land", "the ground," and "the world" as the opposite of the sky. Like our English word "earth," it means both dirt and the planet.
παρελεύσεται, (verb 3rd sg fut ind mid) "Shall...pass away" is from parerchomai, which means "go by", "pass by", "outstrip" (in speed), "pass (time)", "outwit", "past events" (in time), "disregard", "pass unnoticed," "escape notice", and "pass without heeding."
οἱ (article) This is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one" or, in the plural, "the ones."
δὲ (conj) "But" is from de which means "but" and "on the other hand." It is the particle that joins sentences in an adversarial way but can also be a weak connective ("and") and explanation of cause ("so") and a condition ("if"). λόγοι (noun pl masc nom) "Words" is from logos, which means "word", "computation", "relation", "explanation", "law", "rule of conduct", "continuous statement", "tradition", "discussion," "reckoning," and "value."
οὐ μὴ "Not" is from ou me, the two forms of Greek negative used together. Ou is the negative adverb for facts and statements, negating both single words and sentences. Mê (me) is the negative used in prohibitions and expressions of doubt meaning "not" and "no." As οὐ (ou) negates fact and statement; μή rejects, οὐ denies; μή is relative, οὐ absolute; μή subjective, οὐ objective.
παρελεύσονται. (verb 3rd sg fut ind mid) "Shall...pass away" is from parerchomai, which means "go by", "pass by", "outstrip" (in speed), "pass over", "outwit", "past events" (in time), "disregard", "pass unnoticed," "escape notice", and "pass without heeding."