Answered by Shaykh Sohail Hanif, SunniPath Academy Teacher
Answer:
Assalamu alaykum
It is prohibitively disliked (makruh tahriman) to recite the suras of the Qur’an in reverse order consciously in obligatory prayers, though not in voluntary prayers. [Ibn Abidin, Radd al-Muhtar, quoting Tahtawi] If one began, unconsciously, one continues and it does not affect the soundness of one’s prayer. [Haskafi, Durr; ibid.]
However there is no such dislike to memorise the Qur’an in reverse order; in fact it is a very wide spread practice. [Ibn Abidin, Radd al-Muhtar, quoting Tahtawi]
However if one is practising what one has memorised, one should recite the suras in the order that they appear in the Qur’an.
