Answered by Sidi Tabraze Azam
Question:What are the proofs for the forgetful prostration in the Hanafi madhab?
Answer: Assalamu alaikum wa rahmatullahi wa barakatuh,
I hope you are in the best of health and spirits insha’Allah.
According to the Hanafi school, it is a sunna to give one greeting (salam), to one’s right, before performing the two forgetfulness prostrations; after which, one recites the complete tashahud, once again, and finally, performs the final greetings (salams) to end the prayer.
[Shurunbulali, Maraqi al-Falah; `Ala al-Din Abidin, al-Hadiyya al-`Ala’iyya]
The Narrations supporting the Method of performing the Forgetfulness Prostrations
The narrations (hadiths) on this topic are numerous; however, it suffices to mention the following:
 Sayyiduna `Abdullah Ibn Mas`ud narrates that the Messenger of Allah (Allah bless him and give him peace) said, “If one of you doubts in his prayer, let him make a reasonable judgement about the correct (number of cycles) and complete it upon that; then, let him perform a greeting (salam), then let him perform two prostrations” [Sahih al-Bukhari; Sahih Muslim]
 On the authority of Sayyiduna Abu Huraira, “Verily the Messenger of Allah (Allah bless him and give him peace) performed a greeting (salam), then he performed the two prostrations of forgetfulness (sahw) whilst he was sitting, then he performed the (t: final) greetings (salams)” [al-Mujtaba; Sunan al-Nasa’i al-Kubra]
 Sayyiduna Thawban narrates that the Messenger of Allah (Allah bless him and give him peace) said, “For every forgetfulness, there are two prostrations after the greeting (salam)” [Musnad Imam Ahmad; Sunan Abi Dawud]
 Sayyiduna `Abdullah Ibn `Abbas said, “The two prostrations of forgetfulness are after the greeting (salam)” [Tahawi]
 Sayyiduna `Imran Ibn Husain said, regarding the two prostrations of forgetfulness, “One gives the greeting (salam), then prostrates, then gives the (t: final) greetings (salams)” [ibid.]
We have over a thousand years of scholarship that have worked, generation after generation, on the positions, proofs and legal details of the school. May Allah accept all of their efforts and benefit us through them. Amin.
And Allah knows best.
Checked & Approved by Faraz Rabbani