His book Anqasa Amin [Gateway of Faith], written in Geez, was an expansion and scholarly development of his 1532 letter in Arabic to the Muslim invader Ahmad Gran.[37] It is perhaps the only Ethiopian Church writing with so many quotations from and references to the Qur'an ('Ěnbāqom relied on his memory for many of these).[38] The book is polemical, however, and was never popular.[citation needed] The arguments employed by Enbaqom "seem mostly drawn from the standard Arab Christian responses to Islam." For example: Jesus in the Qur'an has greater stature than many Muslims will admit.[39]