Sunan an-Nasa'i 1246
سنن النسائي#1246SahihIt was narrated that 'Abdullah said:"Whoever has doubt, or is not sure, let him estimate what is correct, then let him prostrate twice
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 13:68