Is - (CW) The verb "is" here is the common form of "to be" in Greek. It means to have a certain characteristic or remain in a certain condition. It also equates terms or assigns characteristics. With the genitive object, the sense is "belongs to." The word also means "to exist" and where it doesn't connect to characteristics or conditions. This is an active verb, not the helping verb making "written" passive that it is translated as here."

it -- This is from the third-person, singular form of the verb.

not -- The Greek word translated as "not" is the Greek negative used to deny objective facts, not opinions. It means "no," "not," or"no truly." It makes a negative statement of fact. Adding "really" to the sentence captures the same idea. When a negative precedes the verb, it affects the whole clause. When it precedes other words, its force is limited to those words.

written -- (WT) "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. The form is passive participle of an action completed in the past, "having been written."

in  -- The word translated as "in" means "in," "within," "with" (an instrument), "during" (time),  or "among"  with a dative object as the one here.  With the accusative, it means "into," "on," and "for." When referring to time, it means "during." It can mean "on," "at," or "by" in the sense of "near."

your -- The word translated as "your" is a plural, second-person pronoun in the genitive case. This pronoun follows the noun so the possessive "of yours."

missing "the"  -- (MW) The untranslated word is the Greek definite article,"the," 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. 

Law, -- The Greek word translated as "law" describes the social norms, which can be from "tradition," "common practice," or the "laws." Jesus uses it to refer to the first five books of the OT written by Moses. He did not use it to refer to civil or Roman law. See this article.

missing "that"  -- (MW) The untranslated word "that" introduces a statement of fact or cause, "for what," "because," "since," and "wherefore."

I -- The pronoun "I" is used here. Since, as the subject of the sentence, it is part of the verb, its explicit use accentuates who is speaking "I." Saying "I myself" captures this feeling in English.

missing "myself" -- (MW)  The subjective pronoun repeats the information in the verb so it should be repeated in English like "I myself."

have -- (WT) This helping verb "have" indicates that the verb is the tense indicating an action completed in the past. This is not the tense of the verb here.

said,   - The word translated as "speak" means "to say" and "to speak." It is one of the two most common words translated "speak," "say" and "tell," but it has more a sense of addressing and proclaiming.

You -- This is from the second-person, plural form of the verb.

are -- The verb "are" here is the common form of "to be" in Greek. It means to have a certain characteristic or remain in a certain condition. It also equates terms or assigns characteristics.

gods?  -- The word translated as "gods" means "God" and "deity." It is introduced with an article, so "the God," "the Divine" or "the divine one." Jesus often uses it this way perhaps to indicate the one God as opposed to the pagan gods. It is plural.