that they are hypocrites: "Go back behind you and seek light." So they went back behind them and found nothing; at that point, the deception of Allah overtook them.

[And a wall will be set up between them, having a door] Mujahid’s interpretation: The wall is al-A'raf. [Inside it is mercy] which is Paradise, [and outside it is torment] by means of the Fire.

Yahya said: And al-A'raf is Mount Uhud, according to what has reached me, which is manifested on the Day of Resurrection between Paradise and Hell.