What is Sidr?
A modern Qur’an commentary entitled Tafsīr al-karīm al-raḥman fī tafsīr kalām al-manān by Abd ar-Rahman ibn Nasir as-Sa’di, while commenting on Quran 53:14, the Sidrat al-Muntahā, (Lote-Tree of the Extremity) explained
It [the Sidrat al-Muntahā] is a very large Tree (شَجَرَة – shajarah) beyond the 7th heaven. It is named the Sidrat al-Muntahā because there terminates at it whatever ascends from the earth and whatever descends [from heaven] including what comes down from God, including waḥy (divine inspiration) and other things besides. Alternatively, [it might be said that this name is because] it is the Uttermost Extremity or the very end of something [ or Boundary] (اِنْتِهاء – intihā’ which is one of the many Arabic words for the word end) for the knowledge of the creatures approaching it, relative, that is, to its Existent Being [as located] above the heavens and the earth. So it is al-Muntahā (the Extremity, Boundary) with respect to [all human] modes of knowledge (عُلُوم – ʻulūm) or other things besides. And God is best informed [of this matter]. Thus [it was that] Muhammad saw Gabriel in that location (الْمَكَان – al-makān) which is the Domain of the Pure and Beautiful, Elevated [celestial] Souls (مَحَلُّ الْأَرْوَاحُ الْعُلُوِيَّةُ الْزَّكِيَّةُ الْجَمِيلِيَّة – maḥall al-arwāḥ al-ʻuluwiyyah al-zakiyyah al-jamīliyyah)…— (As-Saʻdi, Tafsir, 819).
Abdullah Yusuf Ali, whose The Holy Qur’an: Text, Translation and Commentary are among the most widely known English versions of the Qur’an, explained that this tree “marked the bounds of heavenly knowledge as revealed to men, beyond which neither Angels nor men could pass.
George Sale, the 18th-century English scholar, has “beyond which Angels themselves must not pass; or, as some rather imagine, beyond which no creature’s knowledge can extend.” The sale also notes that one commentator states that line 16 refers to the “host of angels worshipping” around the tree and another that it is about the birds which sit on its branches.
The 19th-century English explorer, Richard Burton reported seeing an ancient Sidr tree in the mosque containing Muhammad’s tomb in Medina. It was in a garden dedicated to Muhammad’s daughter Fatimah. The fruit from the tree was being sold to pilgrims and its leaves used for washing dead bodies.