Insha-Allah can the salafi brothers help me in taking this question to the 'ulamaah be'ithni'Llah.
Q:We were making salaah behind a brother who made az-ziyaadah (an addition) in the Fajr prayer (making a 3rd rakaah) and when we reminded him of the addition, he acknowledged that he forgot but completely refused to make the sajda as'sahoo due to him deeming it was not necessary for him to do so. What should we do from those who were lead by him regarding the completeness of our salaah?
asalaamu calaykum akhii insh allah you could look at this book it is very beneficial with regarding this issue.It is called "Prostration due to Forgetfulness in the Prayer ? Sujood as-Sahw" by Al-Alaamah ibnu cuthaymeen rahimaahuallaah
and also tapes by shaikh fawzi al-athari called "Sajdatus-Sahw (Prostration for Forgetfulness in the Prayer") (4)