A lot is going on in this verse. It is another example of something that sounds different spoken than written. It also seems to the answer to a question since doesn't explain the previous verse directly. In Greek, it almost reads like Jesus is trying to remember the verse when paraphrasing it and explaining it. So he uses an article, "the " or "the one", several times to refer to the verse. A verse from Isaiah ( Isa 53:12) is what he is paraphrasing here.

The quote is a paraphrase because it uses the same keywords, but a different preposition. This is, of course, all lost in the KJV, which tries to smooth out the verse into a well-written form. The verse in Isaiah uses two uncommon words for Jesus, and he uses them here and in a similar verse in Mark (Mark 15:28). One of these uncommon words is the verb form of the word usually translated in the Gospels as "word". Can you spot it?

The word translated as "for" introduces a reason or explanation so "because" and, in questions, "why." However, since this word always appears in the second position, it is more like an aside remark like, "as an explanation" or "as a cause". 

The word translated as "I say" is the most common word that means "to say," and "to speak," but it also means "to teach," which seems to be the way Christ uses it more frequently. It also has many ancillary meanings such as "to count" ("to number" or like we might say, "to recount" a story) or "to choose for yourself." Christ usually uses this word to refer to his own speaking or teaching.

The Greek pronoun "unto you" here is plural and in the form of an indirect object, "to you", "for you", etc. 

The word translated as "that" introduces a statement of fact or cause.

"This" is a demonstrative pronoun that means "this", "here", "the nearer," and "the familiar."

The word translated as "that" 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.  This word in exactly this form is repeated several times in this verse. This is very noticeable because it usually appears with a noun, but it doesn't anywhere here.

"Is written" is the Greek verb that  means "to mark", "to express by written characters", "to write a letter", "to write down [a law]", and so on. This is how Jesus always refers to the ancient writings of his people. The form is not just passive, but a past tense indicated something completed in the past, "has been written".

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.  

There is no Greek adverb "yet" in this verse. 

"Be accomplished" is translated from a Greek word, which means "to complete" and "to accomplish," especially in the sense of having a goal. It also means "to bring to perfection." The form is passive referring to a specific point in time. This is the verb form of the noun used as the end of this verse, which is translated as "end". This noun is discussed in this article on the "end" of the world.

The word translated as "in" also means "within", "with," or "among." However, as an instrument or manner, it also means "by" which seems to the sense here.

The "me" is in the indirect object form on the first-person pronoun, so usually "to me", though the form has other uses in Greek. 

An untranslated Greek article, "the," or "the one" appears here. The Greek article is much closer to our demonstrative pronouns ("this", "that", "these", "those"). See this article for more. It is in the same form as it was used earlier to refer to "what has been written".

What follows is the paraphrase of a line of Isa 53:12 from the Septuagint.

The Greek word translated as "and" is used as the conjunction "and", but it also is used to add emphasis ("also").

"He was reckoned" is from an uncommon verb for Jesus that means to "count", "reckon or calculate," "set down one's account," "take account," "consider", "conclude", or "infer".  This is the verb form of the word usually translated in the NT as "word", but which doesn't mean that. Most about the noun form of this word in this article.

"Among" is the Greek word that usually means "with" or a related concept such as "among" or "by the means of". It also refers to "after" or "behind" when referring to a place, time, or pursuit. In the version in Isaiah, this preposition is the Greek on usually translated as "in", which is used above.

"The transgressors" is another uncommon word for Jesus, also from the Greek Isaiah, that means "lawless", "impious," and "illegal". It too comes from Isaiah, but the form is different because the different preposition requires a different form. It does not appear with an article here, "the", but it does in Isaiah.

The word translated as "for" introduces a reason or explanation so "because" and, in questions, "why."   However, since this word always appears in the second position, it is more like an aside remark like, "as an explanation" or "as a cause".

The word translated as "the things" 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. However, this word is not in it plural form, "the things" but in the singular form that is used above to refer to "what is written."

The Greek word translated as "concerning" means It means "around" when referring to a place, but, in this context, it means "about", "concerning", "on account of," and "in regard to." This is the way Christ usually uses it.

"Me" is the regular first-person pronoun in Greek in the possessive form, so "my" or "of me".

The word translated as "have" means to "have", "possess", "bear", "keep close", "have means to do",  "to have due to one", or "keep" and so on.

The word translated as "end" means "purpose", "outcome", "something done," or "goal." This noun is discussed in this article on the "end" of the world.