Does the Hadith, "Whoever observes four rak'ahs before Dhuhr and four after it, Allah will forbid him from the Fire," include making up the pre-Dhuhr Sunnah prayers after Asr or Dhuhr, or must they be performed before Dhuhr to be considered as observing them?

The hadith about the two supererogatory (nafilah) prayers of Dhuhr is authentic. If the four raka'at before Dhuhr are missed, it appears that making them up does not substitute for performing them on time, due to the prohibition of praying after Asr, and because that would make the Dhuhr supererogatory prayer eight raka'at, which has not been mentioned in the Sunnah.

However, if the supererogatory prayer is missed due to an excuse such as sleep or forgetfulness, then it is not considered truly missed. Whoever intended to perform Qiyam al-Layl (night prayer) but was overcome by sleep, what he intended is recorded for him. Allah has also overlooked for this Ummah mistakes and forgetfulness.