Abu Dawud
Prayer
Book Number: 002 / Hadith Number: 906
Narated By Al-Miswar ibn Yazid al-Maliki : The Apostle of Allah (pbuh) recited - Yahya (sub narrator) said: Sometimes al-Miswar said: I prayed along with the Apostle of Allah (pbuh) and witnessed that he recited - the Qur'an during the prayer and omitted something (i.e. some verses inadvertently) which he did not recite.
A man said to him: Apostle of Allah, you omitted such-and-such verse. The Apostle of Allah (pbuh) said: Why did you not remind me of it?
The narrator Sulayman said in his version: He (the man) said: I thought that it (the verse) was repealed.