Within the science of Hadith (Mustalah al-Hadith)—Al-Idraaj (الإدراج) refers to the insertion or interpolation of additional words into a narration. A hadith that contains such an addition is called a Mudraj (مدرج) hadith.
Studying-Islam

This occurs when a narrator adds their own explanatory words, comments, or personal statements into the text (matn) or the chain of narrators (isnad) without explicitly separating them from the original hadith. As a result, a listener or reader might mistakenly believe that the narrator’s added words are the exact words of Prophet Muhammad صلى الله عليه وسلم.

Most of the time, Al-Idraaj is entirely unintentional. A narrator might insert words to:

• Explain a difficult word: Clarifying an archaic Arabic term used by the Prophet so the audience understands it.
• Provide context or a ruling: Mentioning an Islamic jurisprudential ruling derived directly from the hadith.
• Combine statements: Merging two different hadiths into one statement for the sake of brevity.

If the narrator fails to pause, change their tone, or clearly state “meaning…” or “and [Companion] said…”, the student writing it down might record the entire sentence as one continuous quote from the Prophet صلى الله عليه وسلم.

In Mustalah al-Hadith, classical scholars point out that Al-Idraaj occurs in sayings (Ahadith Qawliyyah) but does not occur in actions (Ahadith Fi’liyyah).

Example: The Cave of Hira

To understand how meticulously Hadith scholars analyzed texts, consider the famous narration of the Prophet Muhammad (PBUH) receiving the first revelation. Narrated by Aisha (may Allah be pleased with her) and recorded in Sahih al-Bukhari, it reads:

“The commencement of the Divine Inspiration to Allah’s Messenger (PBUH) was in the form of true dreams… Afterward, the love of seclusion was bestowed upon him. He used to go in seclusion to the cave of Hira where he used to practice Tahannuth—and that is worship—for a number of nights before returning to Khadijah to take his food provision…”

Spotting the Hidden Insertion

At first glance, this reads as a single, uninterrupted quote from Aisha. However, the phrase “and that is worship” (wa huwa al-ta’abbud) is a classic example of Al-Idraaj (an unintentional insertion) occurring squarely in the middle of a text.

These are not Aisha’s words. They belong to the later sub-narrator and scholar, Ibn Shihab al-Zuhri.

When transmitting the hadith, Al-Zuhri realized his students might not understand the obscure, ancient Arabic word Tahannuth (يَتَحَنَّثُ). To help them, he paused mid-sentence to quickly define it, then seamlessly continued narrating. Because he did not explicitly say “meaning…”, his students accidentally recorded his definition as part of Aisha’s original statement.

How Scholars Identified It

Scholars like Ibn Hajar al-Asqalani flagged this harmless definition to preserve the original text’s historical purity. They isolated the insertion using two methods:

• Cross-Examination: When comparing this text against other chains of transmission that did not pass through Al-Zuhri, the phrase “and that is worship” was entirely absent.
• Linguistic Logic: Aisha was speaking to contemporaries who already understood native Makkan vocabulary; she would have had no logical reason to define it for them.

Example 2: Merging Fatwa with Prophetic Text

To understand how Hadith scholars separated the Prophet’s exact wording from the legal deductions of later generations, consider the famous narration of Busra bint Safwan regarding ablution (wudhu).

As transmitted by the narrator Abdul Hamid ibn Ja’far, the text reads:

The Prophet (PBUH) said: “Whoever touches his penis, or his testicles, or his groin, let him perform wudhu.”

Spotting the Hidden Insertion

The authentic words of the Prophet (PBUH) are only: “Whoever touches his penis, let him perform wudhu.”

The phrase “or his testicles, or his groin” is an Idraaj (insertion). These are not the Prophet’s words, but rather the personal legal deduction (fatwa) of the great sub-narrator, Urwah ibn al-Zubayr. Urwah deduced that touching surrounding areas carried the same ruling and would teach this alongside the hadith.

When a later narrator—Abdul Hamid ibn Ja’far—transmitted this lesson, he accidentally blended Urwah’s personal commentary with the Prophet’s statement, creating one continuous quote.

How Scholars Identified It

Early Hadith scholars, such as Imam al-Daraqutni, caught this error through rigorous cross-examination. They looked at the transmission of more precise students, who correctly separated the two statements.

These top-tier students narrated the exact prophetic quote, paused, and explicitly added: “And Urwah used to say: ‘If one touches his groin or his testicles…’” By comparing these chains, scholars successfully extracted Urwah’s fatwa from the original text.