"When Allah's Messenger sat for the first two Rak'ah it was as if he was on hot stones." Shu'bah (one of the narrators) said: "Then Sa'd's lips moved (saying) something. So I said: 'Until he stood?' He said: 'Until he stood.'"
Jami` at-Tirmidhi Book 2, Hadith 218
← Previous Hadith "Al-Mughirah bin Shu'bah les us in Salat. When he prayed two Rak'ah he stood without sitting. Those who were behind him said 'Subhan Allah' and he indicated to them that they should stand. He said the Taslim when he had finished his Salat and he performed two prostrations of As-Sahw, and said the Taslim. He said that Allah's Messenger did this."

Jami` at-Tirmidhi Book 2, Hadith 217 Next Hadith → "I passed by Allah's Messenger (S) while he was performing Salat, so I said greeted him with Salam, and he returned it by making signals." He said: "I do not know except that he said: 'He indicated with his finger.'"

Jami` at-Tirmidhi Book 2, Hadith 219