Must Sujud as-Sahw be performed immediately after remembering an oversight, or is there a consideration for the length of the interval?
Chapter on the Two Prostrations of Forgetfulness
Al-Mughni
Book of Prayer
Primary text
One must perform Sujud as-Sahw if one remembers the oversight while still inside the mosque, irrespective of whether one spoke or not. This is the view of Malik, Al-Awza'i, Ash-Shafi'i, and Abu Thawr. The ruling is based on the narration of Ibn Mas'ud that the Prophet (peace be upon him) prostrated after the salutation and speech, and the Hadith regarding the five-rak'ah prayer where speaking occurred before the prostrations. Furthermore, if completing two units of prayer after speech and turning away is permissible (as in the Hadith of Dhu'l-Yadayn), then performing prostrations is more deserving of permissibility.
Supporting text
There is a difference of opinion regarding the measure of a long interval. According to Al-Kharqi, one prostrates if the time interval keeps one within the mosque; if one leaves the mosque, one does not prostrate. This is attributed to Ahmad, and is the position of Al-Hakam and Ibn Shubrumah. Al-Qadi holds that the determination of a long or short interval is based on customary practice, which is the view of Ash-Shafi'i, citing the narration where the Prophet (peace be upon him) returned to the mosque in the Hadith of 'Imran ibn Husayn. Another narration attributed to Ahmad, and a second view of Ash-Shafi'i, states that one prostrates even if one leaves and moves far away, as it is a type of compensation similar to compensating for Hajj. Malik's view is that if the oversight was an addition, one performs it unless the interval is long; however, if it was for a deficiency, it is performed unless the interval is long, as it is for completing the prayer.