The present article investigates the signification of miracle to the prophet’s prophethood from the rational and logical viewpoints in the context of Islamic theology. After proving the necessity of the prophethood with the help of the ‘Rule of Grace’, most of the Islamic theologians consider miracle as the main reason for affirming the claim of someone who claims God has called him to prophethood. Most of theologians maintain that miracle is enough evidence for affirming such a claim, but a few of them criticize this idea. That the miracle rationally signifies the prophethood, and being called by God as a messenger can be stated in two ways. One is that the mere issuing of a miracle by the claimant to prophethood can rationally and logically affirm his prophethood. The other is that by adding some introductory items to the miracle and compiling an authentic logical deduction, one can affirm someone’s claim to prophethood. It seems that both explanations are defective. The deficiency of the first explanation is that the miracle in itself has no logical signification to prophethood and affirmation of the claimant. At most, it shows the agent’s power to perform extraordinary actions, not more. The second explanation is faced with numerous critiques such as vicious circle in argument, deficiency in attributing miracle to God, simultaneous fallacy, deficiency in being miracle as a sign of prophethood, non-homogeneity of reason and claim, the drawback of miracle’s being extraordinary, criticizing the premises of the argument, and the prophethood’s no need for miracle. Finally, the result of the present study is that miracle has no rational signification for prophethood, and prophethood and guiding the human beings do not necessarily require miracle.