Mukhtasar Bukhari

Umm al-Mu'mineen Aisha Siddiqa (may Allah be pleased with her) said that a Bedouin came to the Prophet Muhammad (peace be upon him) and said, "You kiss children, but we do not kiss them." The Prophet (peace be upon him) replied, "What can I do if Allah has not placed mercy in your heart (so how can I put it there now)?"