Sahih al-Bukhari 4613
Sahih al-Bukhari · Book 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) · Allah's Statement: "Allah will not punish you for what is unintentional in your oaths..." (V.5:89)
Narrated `Aisha:
حَدَّثَنَا عَلِيُّ بْنُ سَلَمَةَ ، حَدَّثَنَا مَالِكُ بْنُ سُعَيْرٍ ، حَدَّثَنَا هِشَامٌ ، عَنِ أَبِيهِ ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ أُنْزِلَتْ هَذِهِ الآيَةُ {لاَ يُؤَاخِذُكُمُ اللَّهُ بِاللَّغْوِ فِي أَيْمَانِكُمْ} فِي قَوْلِ الرَّجُلِ لاَ وَاللَّهِ، وَبَلَى وَاللَّهِ.
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."