Musnad Ahmad 944:36

'Amir ibn Salih al-Zubayri narrated to us, Yunus ibn Yazid narrated to me, from Ibn Shihab, from 'Umarah ibn Khuzaymah ibn Thabit al-Ansari—and Khuzaymah is the one whose testimony the Messenger of Allah (may Allah bless him and grant him peace) made equal to the testimony of two men. Ibn Shihab said: 'Umarah ibn Khuzaymah informed me, from his paternal uncle, who was one of the companions of the Messenger of Allah (may Allah bless him and grant him peace): That Khuzaymah ibn Thabit saw in a dream that he was prostrating upon the forehead of the Messenger of Allah (may Allah bless him and grant him peace). He came to the Messenger of Allah (may Allah bless him and grant him peace) and mentioned that to him. The Messenger of Allah (may Allah bless him and grant him peace) lay down for him, and he prostrated upon his forehead.