One of the fundamental questions about Mohammedan revelation is "what is its scope"? In other words, which parts of the Holy Prophet's sayings are rooted in revelation and which parts were based on independent reasoning or according to his everyday life? The third and fourth verses of Chapter 53 (Al-Najm, The Star) provide important data to answer the question, from which Muslim scholars have exerted and provided different information. Representing the correct view about the scope of Mohammadan revelation on the basis of these verses, the present paper reviews and evaluates commentators' view in this regard. Based the interpretation of these verses according to the method of interpreting the holy Quran by the Quran, the findings indicate that these verses only show that the holy Quran is revealed, not the holy Quran and beyond it, as some commentators have regarded Prophet Muhammad's non-Quranic sayings as revealed ones through referring to these verse; not anything more than the holy Quran, as some commentators have identified Holy Prophet's sayings about Imam Ali's succession as revealed
