Adbullaah Ibn Sarjis (radhi-yAllaahu 'anhu) said: " I went to see The Prophet (sal-Allaahu 'alayhe wa sallam) and ate from his food and then said to him:
غَفَرَ اللَّهُ لَكَ يَا رَسُولَ للَّهِ
"May Allaah forgive you, O Messenger of Allaah.'
GafarAllahu laka wa Rasoolallahi
Ahmad 5/82, and An-Nasa'i in 'Amalul-Yawm wal-Laylah p. 218, with checking by Dr. Farooq Hamadah.