The Book Concerning the Use of Correct Words (Kitab Al-Alfaz min Al-Adab wa Ghairiha)
Muslim :: Book 27 : Hadith 5595
'A'isha reported Allah's Messenger (may peace be upon him) having said: None of you should say:" My soul has become evil," but he should say:" My soul has become remorseless." This hadith has been transmitted on the authority of Abfl Bakr with a slight variation of wording.