Sahih Muslim | Book 30 | Hadith Number 5736

Narrated by Abu Huraira
Abu Huraira reported that al-Aqra' b. Habis saw Allah's Apostle (may peace be upon him) kissing Hasan. He said: I have ten children, but I have never kissed any one of them,

whereupon Allah's Messenger (may peace be upon him) said: He who does not show mercy (towards his children), no mercy would be shown to him.