Hadith 506480
Chapter 18: Fasting - كتاب الصيام
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، أَنَّ عَاتِكَةَ ابْنَةَ زَيْدِ بْنِ عَمْرِو بْنِ نُفَيْلٍ، - امْرَأَةَ عُمَرَ بْنِ الْخَطَّابِ - كَانَتْ تُقَبِّلُ رَأْسَ عُمَرَ بْنِ الْخَطَّابِ وَهُوَ صَائِمٌ فَلاَ يَنْهَاهَا .
Yahya related to me from Malik from Yahya ibn Said that Atika bint Zayd ibn Amr ibn Nufayl, the wife of Umar ibn al-Khattab, used to kiss Umar ibn al-Khattab's head while he was fasting, and he did not tell her not to.
Reference Muwatta Malik 506480
USC-MSA web (English) reference : Book 18, Hadith 15