Luke 17:25 But first must he suffer many things, and be rejected of this generation.
First, however, it is required of him many thing to be done to him and to be rejected from this type here.
This verse is a restatement of the earlier Luke 9:22.
The Greek word translated as "but" means "but", "however", and "on the other hand". Since it always falls in the second position, translating it as "however" often captures its feeling better.
The word translated as "he" is the Greek word commonly translated as third-person pronouns in English. It is not the subject of the verb, but the object.
The Greek verb translated as "must" is a special verb that means "it is needful," and "there is a need." It is always singular referring to a specific moment in the past, present, or future. It works something like our word "must" but its form is fixed. The "he" here is not the subject but the object of its action.
The verb translated as "suffer" also means "to be treated so" or "to pay a penalty." Its form is a passive infinitive, "to be treated so" or "to pay a penalty".
The word translated as "many things" is an adjective that means many in number, great in power or worth, and large in size. "Great" or "many" is its most common translation. It is plural neutral so "many things".
The Greek word translated as "and" is used five times in this verb. It is the conjunction "and", but it also is used to add emphasis ("also").
Be rejected" is a verb that means specifically "reject on scrutiny", "reject as unfit or unworthy," and "reject for want of qualifications." It is an uncommon verb, used earlier by Jesus only in reciting a bible quote and in a parallel to this verse. It is also in the form of a passive infinitive, "to be rejected as unfit".
The word translated as "by" means "from" in both location and when referring to a source. It is not the way Jesus would have referred to people who were the author of an act. There is a specific word from for doing this. The sense here is much more "from among" these people, not "by" them.
The untranslated word here is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this", "that", "these", "those"). See this article for more.
The "this" is a pronoun that can mean "this" or "that", "here" or "there", the nearer or the further depending on usage. It follows the noun, so, with the article, the sense is "this...here".
The word translated as "generation" means "race", "family", and "generation". The sense is a "type" or a "specimen" of a particular type. Jesus uses this term frequently in criticism, but that criticism seems more aimed at a particular "type" of people than his generation. It is the word from which we get the scientific "genus". With the article, the sense is "this type here".
πρῶτον (adj sg masc acc) "First" is protos. In place, this means "before", "in front," and, as a noun, "the foremost." Of time, it means "former", "earlier," and, as a noun, "the initial." In order, it means "the first." In math, it means the prime numbers. Of rank or degree, it means "superior" or, as a noun, "the highest" or "the best." -- The word translated as "first" takes a lot of different types of "first" meanings from its context. Here, it is technically an adjective but it plays the role of the English adverb "initially."
δὲ (conj/adv) "But" is 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").
δεῖ ( verb 3rd sg imperf ind act ) "Must" is from, dei, which means "needful," and "there is need." --
αὐτὸν (adj sg masc acc) "He" is autos, which means "the same," and the reflexive pronouns, "myself", "yourself", "himself", "herself", "itself," or the oblique case of the pronouns, "him", "her," and "it." It also means "one's true self," that is, "the soul" as opposed to the body and "of one's own accord." In the adverbial form, it means "just here" or "exactly there."
πολλὰ (adj pl neut nom/acc) "Many things" is polus, which means "many (in number)", "great (in size or power or worth)," and "large (of space)." As an adverb, it means "far", "very much", "a great way," and "long." -- The word translated as "many" means many in number, great in power or worth, and large in size.
παθεῖν (verb aor inf act) "Suffer" is from pascho, which means "to have done to one", "to suffer", "to be treated so", "to come to be in a state", "to pay a penalty", "to suffer legal punishment," and "to be ill."
καὶ (conj) "And" is 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."
ἀποδοκιμασθῆναι [uncommon](verb aor inf pass) "Be rejected" is from apodokimazô, which means specifically "reject on scrutiny", "reject as unfit or unworthy," and "reject for want of qualifications."
ἀπὸ (prep) "Of" is apo, a preposition of separation which means "from" or "away from" from when referring to place or motion, "from" or "after" when referring to time, "from" as an origin or cause.
τῆς (article sg fem acc/gen) Untranslated 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."
γενεᾶς (noun sg fem acc/gen) "Generation" is genea, which means "race", "family", "generation", "class," and "kind." It is a form of the word from which we get the scientific word,"genus."
ταύτης (adj sg fem gen) "This" is tauta, which is a referring pronoun meaning "these", "this", "that," and "here." It can mean the nearer or the further depending on usage. As an adverb it can mean "therefore" and "that is why."