صَحِيحُ مُسْلِمٍ
Sahih Muslim 572 g
The Book of Mosques and Places of Prayer
As-Sahw (forgetfulness) in prayer and prostrating to compensate for it
وَحَدَّثَنَاهُ ابْنُ أَبِي عُمَرَ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ الصَّمَدِ، عَنْ مَنْصُورٍ، بِإِسْنَادِ هَؤُلاَءِ وَقَالَ فَلْيَتَحَرَّ الصَّوَابَ .
This hadith has been narrated by Mansur and he said: " He should aim at correctness."
Sahih Muslim, 572 gSahihصحيح