Umar bin Khattab said, "I felt a surge of desire and kissed my wife while I was fasting. I said, 'Messenger of Allah, I did something terrible today. I kissed while fasting.'"He replied, "What do you think if you were to rinse your mouth with water while fasting?"Isa bin Hammad said in his version, "I said, 'There is no harm in that.'"Then the two narrators agreed on the wording.He said, "Then what is the problem?"
حدثنا أحمد بن يونس حدثنا الليث ح و حدثنا عيسى بن حماد أخبرنا الليث بن سعد عن بكير بن عبد الله عن عبد الملك بن سعيد
قال عمر بن الخطاب هششت فقبلت وأنا صائم فقلت يا رسول الله صنعت اليوم أمرا عظيما قبلت وأنا صائم قال أرأيت لو مضمضت من الماء وأنت صائم قال عيسى بن حماد في حديثه قلت لا بأس به ثم اتفقا قال فمه
Sourcing, its isnad is sahih. Ahmad narrated it, 1/21, and Nasai in Kubra, no. 3048, from the hadith of Layth bin Saad through the same route. Ibn Khuzayma graded it sahih, no. 1999, as did Ibn Hibban, no. 905, and Hakim, 1/431, saying it meets the standard of the two Shaykhs, and Dhahabi agreed with him.