The objection identifies a real limitation: Ibn Ishaq's original Sira is lost, and Ibn Hisham did edit the material he received. But that does not make the Prophet's biography worthless or reduce the Quran's interpretation to one late, censored book. It shows that the evidence must be weighed critically, as historians routinely do.
What the objection gets right
Ibn Ishaq (d. around 767 CE) composed the earliest known comprehensive biography of Prophet Muhammad (PBUH), but his work survives mainly through later recensions, especially Ibn Hisham's (d. around 833 CE). In his introduction, Ibn Hisham explains that he omitted material he considered irrelevant, material that would distress or disgrace people, poetry whose attribution he did not accept, and similar items.
A critic can therefore fairly say that the received Sira is not a neutral transcript of Ibn Ishaq. It is an edited version, and some original evidence has been lost. Nor should every report in it be treated as equally certain. Some accounts are late, weakly transmitted, or shaped by literary and theological concerns. That is a serious historical caution.
Why this does not collapse the evidence
First, Ibn Ishaq is not the same as Ibn Hisham. Ibn Ishaq lived roughly a century after the Hijra, not several centuries later, and his material was transmitted through students and preserved in other early works. Reports associated with his tradition also appear in al-Tabari and other historical writings. Ibn Hisham's omissions are a loss, but they do not erase the wider network of transmission.
Second, the Prophet's life is not reconstructed from the Sira alone. Evidence comes from the Quran, hadith collections, early maghazi and biographical works, genealogical reports, legal traditions, poetry, and the accounts of transmitters who sometimes preserve different versions of the same event. These sources are not all equal, but comparison allows stronger reports to be distinguished from weaker ones. Classical Muslim scholars themselves did this through scrutiny of chains, transmitters, wording, chronology, and agreement with better-established evidence.
Indeed, in the Messenger of Allah you have an excellent example for whoever has hope in Allah and the Last Day and remembers Allah often.
Quran 33:21
This verse establishes the religious importance of knowing the Prophet's example, but it does not require accepting every detail found in a later biography. The Quran itself supplies an early framework, while hadith criticism and corroboration supply further controls. Nor does a biographer's omission prove that the omitted material was true; it proves only that we no longer possess all of Ibn Ishaq's compilation.
What the argument does and does not establish
It establishes that the Sira must not be read uncritically, and that some details remain uncertain. It does not establish that the Prophet's life is fictional, that Ibn Hisham invented the received narrative, or that Quranic interpretation rests on one late source. The central outline of the Prophet's mission, preaching, persecution, migration, community, and death is supported by several overlapping early traditions.
The honest conclusion is qualified confidence: particular reports require examination, while the broad historical picture remains well grounded.