The One Who Does Not Show Mercy Will Not Be Shown Mercy

 Aboo Hurairah (may Allaah be pleased with him) said: The Messenger of Allah (blessings and peace of Allaah be upon him) kissed al-Hasan ibn ‘Ali, when al-Aqra‘ ibn Haabis al-Tameemi was sitting with him. al-Aqra‘ said: I have ten children and I have never kissed one of them. The Messenger of Allaah (blessings and peace of Allaah be upon him) looked at him, then he said: “The one who does not show mercy will not be shown mercy.”

[Bukhari 5997]