إِذ يَغشَى السِّدرَةَ ما يَغشىٰ

When there covered the Lote Tree what covered it.

EXPOSITION

The tree was covered by that which defies description. Like verse 10 of this surah, the usage of the unknown passive highlights the enigmatic nature of the affair and its immensity. This similar structure of expression is repeated in the surah, as it ties into the mysterious nature of the main theme, as we also read later, Covering it with what covered it (verse 54).

INSIGHTS FROM HADITH

There are various reports, some of which have been attributed to the Prophet, that claim the tree was covered by golden butterflies; or the light of God; or that it was covered by angels like crows that cover a tree when they perch on it.^{‎[1]Tibyan, 9/426; Tabari, 27/33; Qurtubi, 17/96.} This latter would fit in with the hadith we quoted earlier about angels sitting on every one of its leaves.^{‎[2]Tabrisi, 9/265.} What is most correct is to say we do not know what covered it because it defies description.

REVIEW OF TAFSĪR LITERATURE

Rāzī suggests that since the tree is located at a place which cannot be passed by the angels, it has become like a place of congregation for them – something akin to the Kaaba for mankind – and this is why it is reportedly covered by the angels, as we read in some narrations.^{‎[3]Razi, 28/245.}

[1] Tibyan, 9/426; Tabari, 27/33; Qurtubi, 17/96.
[2] Tabrisi, 9/265.
[3] Razi, 28/245.