Key terms, pulled from the book’s definitions section, for keeping the discussion precise.
Derives from the Arabic root s-l-m, meaning “submission” or “surrender” (to God)[1][2]. As a term, it denotes the monotheistic religion founded by the Prophet Muhammad in 7th-century Arabia, centered on complete submission to the one God (Allah). A follower of Islam is called a Muslim, meaning “one who submits (to God)”[1]. In Islamic theology, islām also implies achieving peace through surrender to God’s guidance.
In a religious context, “submission” refers to yielding one’s will to the will of God. In Islam, this is not seen as passive resignation but as an active, willing obedience to God’s commands. The Qur’an often describes prophets and righteous individuals as those who “submit” to God (muslim in a generic sense). For example, Abraham is described as having “submitted himself to God” (Qur’an 2:131), embodying the ideal of submission. Thus, Islam (submission) is both the name of the faith and the core of its practice[1].
An adjective referring to the religious traditions tracing their origin to the patriarch Abraham. “Abrahamic religions” typically denote Judaism, Christianity, and Islam – all of which revere Abraham and see him as a forefather in faith[3][4]. These religions share belief in one God and certain narratives (like the story of Abraham’s trials), though they differ in theology and law. The term is modern and somewhat contested; it emphasizes common heritage, but scholars note it can oversimplify differences[5][4].
The institution or concept of being a prophet (nubuwwah in Arabic). In Islam, prophethood is a divine favor – a prophet (nabī) is a human chosen by God to receive revelation (waḥy) and convey God’s message to people[6]. Belief in all prophets is a pillar of Islamic faith (Qur’an 4:136). The Qur’an presents prophethood as a corollary of belief in God – a necessary link for humans to receive guidance[7]. In Judaism, prophets (Hebrew nāviʼ) are individuals who speak for God (like Moses, Isaiah); they are often social critics and religious teachers. In Christianity, prophecy is affirmed in the Old Testament and John the Baptist, and Christians see Jesus as the culmination of prophethood (as well as more than a prophet). Notably, Islam distinguishes between prophets (many, including those sent to their own people) and messengers (rasūl, those given a new scripture or law). Muhammad is regarded as both prophet and messenger, and “Seal of the Prophets” (Khātam al-Anbiyā’ – final prophet) in Islam.
In a religious sense, revelation (waḥy in Arabic) is the act of God disclosing divine truth or knowledge to humans, usually through chosen individuals. It is communication from God to mankind[8]. For example, Muslims believe the Qur’an is a verbatim revelation from God to Muhammad via the Angel Gabriel. In the Bible, the prophets often preface their messages with phrases like “The word of the Lord came to…” indicating revealed guidance. Christian theology distinguishes between General revelation (God’s self-disclosure in nature and conscience) and Special revelation (direct communication through scripture, prophetic inspiration, and in Christian belief supremely through Christ). All Abrahamic faiths see their holy scriptures as products of divine revelation (inspired or dictated), though the modes (e.g. verbatim dictation in Islam vs. inspired authors in Christianity) differ.
A body of sacred, authoritative writings in a religious tradition. Scriptures are the “revered texts, or Holy Writ, of the world’s religions,” distinguished by being regarded as sacred and foundational by the community of believers[9]. For example, the Hebrew Bible (Tanakh) is Jewish scripture, the Bible (Old and New Testaments) is Christian scripture, and the Qur’an is Islamic scripture. Scriptures are believed to contain divine guidance or truth; Jews and Christians view their scriptures as inspired by God, and Muslims view the Qur’an as the direct word of God. These texts often form the basis for law, theology, and worship. The degree of literalness and interpretation accorded to scripture can vary: e.g. Muslims assert the Qur’an’s textual perfection in Arabic, while Christians acknowledge the Bible’s divine message worked through human authors. Canon formation is the process by which a community recognizes certain texts as scripture.
Taḥrīf (Arabic: تحريف, “distortion” or “alteration”) in Islamic discourse refers to the corruption of previous scriptures. In Islam, it is taught that earlier revelations – notably the Torah and the Gospel – were subject to human interference, either by textual alteration (changing or omitting words) or interpretive distortion (misrepresenting meanings)[10][11]. The Qur’an accuses some among the People of the Book of “twisting words from their context”[12] (see Qur’an 5:13, 4:46) and concealing truth. Muslim scholars historically debated whether taḥrīf was primarily textual (actual changes in the manuscripts) or merely interpretive (corrupt explanation)[11]. The prevailing traditional view, especially among medieval scholars like Ibn Ḥazm, was that Jewish and Christian scriptures no longer exist in a fully pristine form – hence the Quran is needed as the final, protected revelation[12]. Modern academic and interfaith perspectives note that many biblical manuscripts predate Islam, suggesting the texts were generally stable, but from an Islamic standpoint any doctrinal deviations (e.g. deifying Jesus) are attributed to taḥrīf in scripture or its interpretation.
The belief in a single, unique God. In classical definition, monotheism is the belief in the existence of one God, or the oneness of God, as opposed to polytheism (belief in many gods)[13]. All three Abrahamic religions are monotheistic, though their conceptions of God differ. In Judaism, God (YHWH) is absolutely one (as affirmed in the Shema: “Hear O Israel, the Lord is our God, the Lord is One” – Deuteronomy 6:4). Islam emphatically teaches God’s oneness (tawḥīd) – e.g. “He is Allah, One” (Qur’an 112:1) – allowing no division of person or being. Christianity also insists there is only one God, but in mainstream doctrine God’s oneness includes a Trinity of three coeternal Persons (Father, Son, Holy Spirit). This is sometimes called “trinitarian monotheism,” which Muslims and Jews contend is a modified form of monotheism. All Abrahamic faiths view the one God as the sovereign creator, but attribute different qualities (for instance, the Christian view of God includes the incarnation in Jesus, which Islam and Judaism reject). Monotheism historically provided a basis for universal ethics and law in these religions, since one God implies a single moral authority for all humanity[14].
In Christian theology, the Trinity is the doctrine that God is one Being in three Persons. It teaches that the one God “exists in three coeternal, consubstantial divine persons: God the Father, God the Son, and God the Holy Spirit”, who share one essence or substance[15]. This doctrine emerged from early Christian attempts to reconcile the divinity of Jesus and the Holy Spirit with strict monotheism. The term “Trinity” isn’t in the Bible, but Trinitarian Christians cite verses like Matthew 28:19 (baptizing “in the name of the Father, Son, and Holy Spirit”) and 2 Corinthians 13:14. The Trinity doctrine was formalized in church councils (Nicaea 325 CE and Constantinople 381 CE)[15]. Nontrinitarian groups (like Arians historically, or modern Unitarians) view this as a later development and not true monotheism. Both Islam and Judaism reject the Trinity, seeing it as incompatible with the indivisible oneness of God (the Qur’an, for instance, criticizes the idea of God having a “son” or partners – Qur’an 4:171, 5:73). From a Christian perspective, however, the Trinity does not negate monotheism but defines God’s internal relational reality. It remains a primary theological difference among the Abrahamic faiths.
In Christianity, the Incarnation is the belief that God became human in the person of Jesus Christ. More precisely, it holds that “the pre-existent Divine Person of God the Son… was made flesh by being conceived… in the womb of the Virgin Mary”, such that Jesus is fully God and fully man[16]. This is encapsulated in John 1:14: “The Word became flesh and dwelt among us.” The Incarnation doctrine, formalized at the Council of Chalcedon (451 CE), teaches that in Jesus, one person unites both a divine nature and a human nature[16]. This belief is unique to Christianity – it underpins ideas like atonement (God taking on human nature to redeem humanity). Judaism and Islam both sharply disagree with the Incarnation. Judaism expects a human messiah, not God in flesh. Islam considers Jesus a great prophet and messiah but strictly human, and the Qur’an declares that God does not become man (and has no sons): “It is not appropriate for the Most Merciful that He should take a son” (Qur’an 19:92). The Incarnation thus is a defining Christian tenet that marks a theological split: for Christians it exemplifies God’s intimate involvement in salvation, whereas for Muslims and Jews it conflicts with divine transcendence and unity.
A covenant is a solemn agreement or promise that establishes a relationship with mutual obligations, often between God and humans. In the Bible, covenants are a key framework: e.g. God’s covenants with Noah, Abraham, Israel at Sinai, David, and the “New Covenant” in Jeremiah. “In biblical theology, a covenant is a solemn agreement or promise between God and humans, often involving commitments and obligations.”[17] For instance, God’s covenant with Abraham (Genesis 15, 17) promised descendants and land, with circumcision as the sign. The Mosaic Covenant (Exodus 19-24) gave the Law; Israel’s obligation was obedience, and God’s was blessing/protection. Christianity speaks of a “New Covenant” (prophesied in Jeremiah 31:31–34, instituted by Jesus at the Last Supper – Luke 22:20) which emphasizes internalizing God’s law and universal forgiveness through Christ. In Judaism, covenant (brit) is central – especially the Sinai covenant which makes Israel the Chosen People bound to the Torah. In Islam, while the term “covenant” (Arabic mīthāq or ʿahd) appears (e.g. Qur’an 2:124, 33:7), the concept is less central as a theological category. The Qur’an mentions God’s covenants with the prophets and with the Children of Israel, and all humans are said to have made a primordial covenant to recognize God (Qur’an 7:172). But the relationship between God and believers in Islam is often framed more as creator-servant and via divine law (Sharīʿa) than the bilateral covenant language of the Bible. Nonetheless, the idea of God’s promise and man’s commitment is present (e.g. Qur’an 2:40, God asks Israel to fulfill their covenant with Him and He will fulfill His with them).
Messiah (from Hebrew Mashiaḥ, “anointed [one]”) refers to an anointed king or savior figure. In Jewish expectation, the messiah is a future leader from David’s lineage who will restore Israel, bring peace, and reign in the name of God. This figure is understood as fully human – “a great, charismatic leader” but not divine[18]. For example, Maimonides described the Messiah as a king who will rebuild the Temple and gather the exiles[19]. In Christianity, “Messiah” (Greek Christos, hence “Jesus Christ”) specifically refers to Jesus of Nazareth, whom Christians believe is the promised deliverer. Christians hold that Jesus fulfilled Messianic prophecies (though in a spiritual sense) and also identify him as the Son of God – a unique divine Messiah very different from the Jewish national hero concept. Thus, in Christian understanding, the Messiah is not only an anointed king but the incarnate Word of God who brings salvation from sin. Islam’s view acknowledges Jesus (`Īsā) as al-Masīḥ (Messiah)[20], a title the Qur’an uses. However, the meaning is not the same as in Christianity – in Islam, Jesus the Messiah is a revered prophet and the miraculously born servant of God, who will play a role in the end times (returning to defeat the false messiah, etc.), but he is not divine, not crucified for atonement (Qur’an 4:157-159), and not a savior from original sin. Essentially, for Muslims, “Messiah” is an honorific for Jesus indicating he is the anointed one in a line of Israelite prophets and perhaps that he is the messianic figure for Jews, but Muslims do not accord it the theological weight Christians do. Meanwhile, Jews do not accept Jesus as the Messiah at all, awaiting a future figure. The term thus highlights a major three-way divergence in interpretation across the Abrahamic faiths.
Paraclete (Greek paraklētos, meaning “one called alongside,” i.e. advocate, helper, or comforter) is a term used in the New Testament, especially in the Gospel of John. Jesus tells his disciples he will ask the Father to send “another Paraclete” after his departure (John 14:16). In John’s context, this Paraclete is identified as the Holy Spirit – “the Spirit of truth” who will teach and guide the believers[21]. (John 14:26 explicitly says, “the Advocate, the Holy Spirit, whom the Father will send in my name…”.) Christians thus understand Paraclete as the indwelling Holy Spirit, the divine presence continuing Jesus’ work after the Ascension. Notably, 1 John 2:1 also calls Jesus a paraclete (advocate with the Father), implying the Holy Spirit is “another advocate” of the same kind. In Islamic argumentation, some have proposed that references to the Paraclete are in fact prophecies about Prophet Muhammad. This Islamic view hinges on the idea that Jesus foretold a coming “Messenger” after him. Muslim writers sometimes claim that the Greek word paraklētos (“comforter/advocate”) might have been confused with or is equivalent to periklutos (“praised one”), which would correspond to Muhammad (meaning “praised” in Arabic). However, there is no manuscript evidence of periklutos in the Gospel text – all known Greek manuscripts read paraklētos[22]. Islamic scholars who make this argument often cite Qur’an 61:6, where Jesus is reported as having given “good news of a messenger to come after me, whose name is Aḥmad” (Aḥmad being related to “the most praised”). Mainstream scholarship (Christian and secular) holds that John’s Paraclete refers to the Holy Spirit, not a human prophet, especially since the text describes the Paraclete as a spirit who will be with believers forever (John 14:16-17). The Paraclete-as-Muhammad interpretation is thus a minority view outside Islamic apologetics. We will explore this further in Section 5, but in summary Paraclete in Christian theology = Holy Spirit Advocate, whereas in some Muslim readings = a coded prophecy of Muhammad; the language and context in John strongly favor the former interpretation[23].
