Early Christian-Muslim Debate on the Unity of God History of Christian-Muslim Relations Editorial Board David Thomas (University of Birmingham) Tarif Khalidi (American University of Beirut) Gabriel Said Reynolds (University of Notre Dame) Mark Swanson (Lutheran School of Theology at Chicago) VOLUME 21 Christians and Muslims have been involved in exchanges over matters of faith and morality since the founding of Islam. Attitudes between the faiths today are deeply coloured by the legacy of past encounters, and often preserve centuries-old negative views. The History of Christian-Muslim Relations, Texts and Studies presents the surviving record of past encounters in authoritative, fully introduced text editions and annotated translations, and also monograph and collected studies. It illustrates the development in mutual perceptions as these are contained in surviving Christian and Muslim writings, and makes available the arguments and rhetorical strategies that, for good or for ill, have left their mark on attitudes today. The series casts light on a history marked by intellectual creativity and occasional breakthroughs in communication, although, on the whole beset by misunderstanding and misrepresentation. By making this history better known, the series seeks to contribute to improved recognition between Christians and Muslims in the future. The titles published in this series are listed at brill.com/hcmr Early Christian-Muslim Debate on the Unity of God Three Christian Scholars and Their Engagement with Islamic Thought (9th Century C.E.) By Sara Leila Husseini LEIDEN | BOSTON Cover illustration: Mar Saba Monastery, Palestine. Photograph by Enas al-Muthaffar, 2014. Library of Congress Cataloging-in-Publication Data Husseini, Sara Leila.  Early Christian-Muslim debate on the unity of God : three Christian scholars and their engagement with Islamic thought (9th century c.e.) / by Sara Leila Husseini.   pages cm. — (History of Christian-Muslim relations ; 21)  Includes bibliographical references and index.  ISBN 978-90-04-27838-7 (hardback : alk. paper) — ISBN 978-90-04-27969-8 (e-book) 1. God— Simplicity—History of doctrines. 2. God (Islam). 3. Christianity and other religions—Islam. 4. Islam—Relations—Christianity. I. Title.  BT148.H87 2014  231’.04409175927—dc23 2014020987 This publication has been typeset in the multilingual ‘Brill’ typeface. With over 5,100 characters covering Latin, ipa, Greek, and Cyrillic, this typeface is especially suitable for use in the humanities. For more information, please see brill.com/brill-typeface. issn 1570-7350 isbn 978 90 04 27838 7 (hardback) isbn 978 90 04 27969 8 (e-book) Copyright 2014 by Koninklijke Brill nv, Leiden, The Netherlands. Koninklijke Brill nv incorporates the imprints Brill, Brill Nijhoff, Global Oriental and Hotei Publishing. All rights reserved. No part of this publication may be reproduced, translated, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission from the publisher. Authorization to photocopy items for internal or personal use is granted by Koninklijke Brill nv provided that the appropriate fees are paid directly to The Copyright Clearance Center, 222 Rosewood Drive, Suite 910, Danvers, ma 01923, usa. Fees are subject to change. This book is printed on acid-free paper. To my mother Mary Elizabeth and my father Rafiq Haidar Husseini For their unwavering love, unending support and utter faith. ∵ Contents Acknowledgements  xi Introduction  1 Part 1 Three Arabic-Speaking Christian Theologians and Their Writings on the Doctrine of the Trinity (c. 800–850) 1 Historical and Intellectual Environment  11 Christians in the Islamic Empire: Historical Social and Linguistic Contexts  11 Historical Context  11 Social Context  12 Linguistic Environment  17 Christian Theologising on the Trinity  21 Philoxenus of Mabbug (d. 523)  24 John of Damascus (c. 675–c. 754)  26 Muslim Theologising on the Nature and Unity of God  30 Abū al Hudhayl (c. 750–c. 840)  33 Ibn Kullāb (d.c. 855)  35 Nature of kalām  37 Muslim Criticisms of the Doctrine of the Trinity  40 2 Theodore Abū Qurra (c. 750–c. 830)  47 Background  47 Biography  47 Historical Context  48 Intellectual Context  51 Works Relating to the Trinity  53 Setting the Context  55 Relationship between Faith and Reason  55 Christianity as the True Religion  56 Explanation of the Trinity  58 Scriptural Proofs  59 Rational Analogies  61 Attributes of God  64 viii contents Response to Muslim Questions  68 Theodore Abū Qurra’s Understanding of the Nature of God  74 3 Abū Rāʾiṭa Al-Takrītī (c. 755–c. 835)  77 Background  77 Biography  77 Historical Context  78 Intellectual Context  79 Works Relating to the Trinity  80 Setting the Context  83 Agreement that God is One  83 Explanation of the Trinity  86 Types of Oneness  86 Absolute vs. Relative Names  88 Response to Muslim Questions  97 Abū Rāʾiṭa’s Understanding of the Nature of God  99 4 ʿAmmār al-Baṣrī (d.c. 840)  105 Background  105 Biography  105 Historical Context  105 Intellectual Context  107 Works Relating to the Trinity  109 Setting the Context  112 What can be Known about God  112 Criticism of the Teaching that God has no ‘Word’ or ‘Life’  115 God’s Relationship to His Word and Life  118 Explanation of the Trinity  120 Four ‘Categories’  120 ‘One and Three’ is Not a Numerical Issue  123 Al-uqnūm and the Relationship Between Substance and Hypostases  124 Biblical Proofs  128 Response to Muslim Questions  131 ʿAmmār’s Understanding of the Nature of God  136 contents ix Part 2 The Role and Function of Christian Explanations of the Trinity in Arabic 5 The Tools of Christian Arabic Apologetic and Polemic  143 Analogy and Metaphor  143 Scriptural Proofs  154 Terminology  161 Rational and Logical Proofs  174 ‘The Unity of Species’  174 ‘A Question for the Muslims’  179 ‘The Headship of God’  179 ‘Three is the Perfect Number’  180 The “Attribute-Apology”  181 6 Christian Theologians Employing Muslim Theology  187 Priorities, Emphases and Engagement with Islamic Thought  187 Abū Qurra  187 Abū Rāʾiṭa  193 ʿAmmār al-Baṣrī  198 The Role of Christian Arabic Works  203 Audience and Purpose  203 The Place of Early Christian Theology in Arabic  205 Conclusion  212 Bibliography  217 Bible of Qur’an Citations  228 Index of People and Places  229 Subject Index  233