Have you observed prayer? He said: No. He (the Holy Prophet) said: Stand and offer the two rak'ahs. According to Qutaiba, the words are:" He said: Offer two rak'ahs."
Sahih Muslim Book 7, Hadith 70
← Previous Hadith This hadith is narrated by Jabir through another chain of transmitters but Hammad (one of the narrators) made no mention of the two rak'ahs.

Sahih Muslim Book 7, Hadith 69 Next Hadith → Have you offered two rak'ahs? He said: No. Upon this he said: Then observe (them).

Sahih Muslim Book 7, Hadith 71