Narrated `Aisha:
This Verse: "Allah will not punish you for what is unintentional in your oaths." (5.89) was revealed about a man's state men (during his talk), "No, by Allah," and "Yes, by Allah."
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 137
Arabic reference: Book 65, Hadith 4613