Hadith 506510
Chapter 18: Fasting - كتاب الصيام
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم كَانَتْ إِذَا ذَكَرَتْ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم يُقَبِّلُ وَهُوَ صَائِمٌ تَقُولُ وَأَيُّكُمْ أَمْلَكُ لِنَفْسِهِ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم
Yahya related to me from Malik that he had heard that A'isha, the wife of the Prophet, may Allah bless him and grant him peace, would say, when she mentioned that the Messenger of Allah, used to kiss while fasting, "And who among you is more able to control himself than the Messenger of Allah, may Allah bless him and grant him peace?"
Reference Muwatta Malik 506510
USC-MSA web (English) reference : Book 18, Hadith 18