Islamic Law requires that a person who is asked to witness in a court should posses essential skills. Before reaching a certain decision between the parties on the basis of „testimony in court‟, the judge is required to start secret and public enquiry into whether or not the witnesses are trust-worthy as well as to establish/determine if the witnesses posses „the qualification of justice‟ during his individual judicial discretion. In this chapter entitled by the author „Tazkiya‟, which means „purification‟, the author was able to briefly and coherently present the topic under such sub-titles as „Muzakki‟s Qualifications‟, „Kinds of Tazkiya" and “The Number of the Muzakkin”