‏الصلاة : Hadeeth No:1726 Ibn Mas'ud reported Allaah's Messenger (sallAllaahu alayhi wa sallam) as saying: Wretched is the man who says: I forgot such and such a sura, or I forget such and such a verse, but he has been made to forget....

‏الفضائل : Hadeeth No:5858 Anas b. malik reported Allaah's Messenger (sallAllaahu alayhi wa sallam) as saying: I came. And in the narration transmitted on the authority of Haddib (the words are): I happened to pass by Moses on the occasion of the Night journey near the red mound (and found him) saying his prayer in his grave....