the Prophet (S) led them in Salat he forgot (something) so he performed two prostrations, then the Tashah-hud, then the Salam.
Jami` at-Tirmidhi Book 2, Hadith 248
← Previous Hadith "The Prophet (S) performed two prostrations after the Salam."

Jami` at-Tirmidhi Book 2, Hadith 247 Next Hadith → "I said to Abu Sa'eed: 'One of us performs Salat and we do not know how (much) we prayed.' So he said: 'Allah's Messenger (S) said: "When one of you performs Salat and he does now know how (much) he prayed then let him perform two prostrations while he is sitting."

Jami` at-Tirmidhi Book 2, Hadith 249