Sahih Muslim Book 043, Hadith Number 7178.
Chapter : Pertaining to the Verse: "Has not the time yet come for the Believers that their Hearts should be humble for the Remembrance of Allah? " (lvii. 16).
Ibn Mas'ud said: Since our acceptance of Islam and the revelation of this verse in which Allah has shown annoyance to us: "Has not the time yet come for the believers that their hearts should be humble for the remembrance of Allah?" (lvii. 16), there was a gap of four years.