http//www.haqeeqat.org.pk/English%20Tafsir%20e%20Haqeeqat/00.%20Tabweeb/0001.%20Pronouns%20and%20Prepositions/Demonstrative%20Pronouns/01.%20Zalika/1.gif It is a noun of indication, properly meaning This. Singular; Masculine; it is used to refer, draw attention, indicate or introduce something or person to the addressee. It is for the person being addressed, singular, second person; masculine. Checking its recurrence in Qur'aan will reveal that its Laam refers to a past fact, or to a just mentioned fact, command, advice. The second noun is also definite with definite article. Read about definite article, it will tell that it is prefixed to a thing which is right in front of you. Here is that book/this is the book wherein you will find all the time you read it, that its contents are absolutely void of psychologically disconcerting suspicious, conjectural, whimsical, conflicting, un-certain, illusory, unsubstantiated, biased and opinionated matter. http//www.haqeeqat.org.pk/English%20Tafsir%20e%20Haqeeqat/00.%20Tabweeb/0005.%20RAIB/1.gif This verbal noun does not mean "doubt". It is the subject noun of the negation particle; a Verbal/Infinitive noun, in Arabic terminology . It is a noun signifying action and state only. It is the source from where the verbs are derived. Its past and present tense verbs are -. Infinitive Noun signifies the action indicated in the verb derived from it. The action that a verb denotes signifies change and alteration of states in time and space, physical or abstract, which was the intent or objective of doing that act. An action causes an effect to take existence; causes a new state to emerge different to that which existed before the execution of action. The Root is " ". states, " -, Infinitive Noun "It occasioned in me disquiet, disturbance, or agitation of mind. This is the primary signification." At page 364 it states; " The primary signification is Disquiet, disturbance, or agitation of mind, and accidents or evil accidents of time that disturb or disquiet the heart and mind. All the critical readers of the books may collectively catalogue all such elements in nonfiction books that might be considered as unpleasant and disquieting even by one reader; and thereafter peruse the Arabic text of Grand Qur'aan only to find that none is present therein. This renders it infinitely reliable and a pleasant read. Introduction of Qur'aan The Infinitely Reliable Book RYB mean doubt based on this verse. http//corpus.quran.com/wordbyword.jsp?chapter=2&verse=23