Sahih Bukhari Volume 001, Book 003, Hadith Number 103.
Narated By Ibn Abu Mulaika : Whenever 'Aisha (the wife of the Prophet) heard anything which she did not understand, she used to ask again till she understood it completely. 'Aisha said: "Once the Prophet said, "Whoever will be called to account (about his deeds on the Day of Resurrection) will surely be punished." I said, "Doesn't Allah say: "He surely will receive an easy reckoning." (84.8) The Prophet replied, "This means only the presentation of the accounts but whoever will be argued about his account, will certainly be ruined."