This study analyzes the discourse of persuasion in Prophet Muhammad’s da’wah letters using a Pragma-Rhetorical analysis approach. It attempts to fill in the gap between the old and the new, the traditional and the modern by developing a blended methodology that marries the ancient rhetoric to the contemporary pragmatics and comes out with Pragma-Rhetorical approach of analysis. One of the aims of this study is to display how Pragma-Rhetorical analysis can reveal some strategies used by the Holy Prophet (peace be upon him) to persuade Kings, rulers, and chiefs of tribes to change their beliefs and convert to Islam through very brief lines. The study tries to show the influence of employing certain contextual and textual devices on shaping the thought and perception and how these devices are used by Prophet Muhammad to persuade the receivers of his da’wah letters and dominate their hearts and minds in a way which makes them change the religion of their fathers and ancestors. In a nutshell, the study proves that Islam was introduced and spread not by the power of sword but rather by the power of the word, peaceful preaching, and persuasion.