. The present paper is divided in to five sections preceded by most important finding arrived at by the researcher The first section seals with oath from language to terminology The second section is devoted to discussing the (Ta'a) of Oath.The third section tackles the Oath by (Ta'a) in the Quranic narrations. The fourth section is concerned with the use of oath within the descriptions of some conditions of Doomsday-Finally the fifth section deals with the use of explicit oath by(Ta'a).