How does the Islamic State in Iraq and Syria (ISIS) leverage Islamic Law to support their strategic objectives? Islam, as most religions, is a defining catalyst of group identity. ISIS has capitalized on this, using it as a vehicle to legitimize its interpretation of Islamic Law. This study builds upon Social Movement Theory to develop and test a conceptual framework of ISIS messaging strategies. This framework highlights the progression of the organization's message from mainstream Islamic Law to radical unified reinterpretation. ISIS leaders' speeches are used to test the model. Ultimately, study findings inform counter-messaging strategies and identify mobilization mechanisms.