The Messenger of Allah kissed al-Hasan ibn Ali (his grandson) and al-Aqra ibn Haabis al-Tamimi was sitting with him. Al-Aqra said: 'I have 10 children and I have never kissed any one of them.' The Messenger of Allah looked at him and said: 'The one who does not show mercy will not be shown mercy on the Day of Recompense.' [Al Bukhari]