Muslim :: Book 35 : Hadith 6523
Allah's Messenger (may peace 'be upon him) said: O people, seek repentance from Allah. Verily, I seek repentance from Him a hundred times a day.
Muslim :: Book 37 : Hadith 6636
If a believer were to know the punishment (in Hell) none would have the audacity to aspire for Paradise (but he would earnestly desire to be rescued from Hell)