While many Christians show interest in studying and understanding Islam, some approach it from a sociopolitical and cultural lens, and others employ historical and theological approaches to comprehend the religion brought forth by Muhammad. One of the earliest and major Christian examples in engaging Islam was John of Damascus (c. 675–754). He identified Muslims as Ishmaelites and Islam as a heresy. In his work, Fountain of Knowledge, he refuted the Ishmaelite Heresy, as he argued that the Islamic understanding of God is inconsistent with Christian teachings about the Triune God and that the Islamic rejection of the divinity of Jesus Christ is a fundamental theological error. Additionally, in his refutation, John tackles other theological issues, including the authenticity of Muhammad’s identity and the authority of the Quran.
In this paper, I will examine John of Damascus’ work and argue that his theological framework for refuting the Ishmaelite heresy can give today’s church insights into the core of the Islamic theology of God (Allah), the identity of Muhamad, and the nature of the Quran for a Christian understanding of Islam today. My goal is to show that John did not engage Islam from a sociopolitical or sociocultural perspective but theologically.
To achieve this, I will first describe John’s refutation of the Ishmaelites. This presentation demonstrates that his understanding of Ishmaelite’s ideology was influenced by a theological framework instead of sociopolitical and cultural angles—I will reflect on this matter as I contrast them with some contemporary approaches. Second, I will examine a brief account of John’s life within his historical and theological context in order to demonstrate that despite the sociopolitical and cultural complexities in his day, he focuses on uncovering the theological core of Islam because the sociopolitical and cultural issues flow from the theological core. Third, I will analyze his understanding of the Ishmaelite ideology, particularly unearthing its theological core based on his Trinitarian theology. Finally, I will conclude with a few observations on the significance of John’s theological framework for evangelism and apologetics to Muslims today.
Ultimately, this paper contributes to the discuss on Christian understanding of Islam in global evangelicalism by showing the significance of John’s approach to understanding Islam for evangelism and apologetics to Muslims today.