Kissing the children and having mercy and clemency towards them
Authentic hadithعن عائشة رضي الله عنها قالت: قَدِمَ نَاسٌ مِنَ الأَعْرَابِ عَلَى رَسُولِ اللهِ صلى الله عليه وسلم فقالوا: أَتُقَبِّلُونَ صِبْيَانَكُمْ؟ فقال: «نعم» قالوا: لَكِنَّا واللهِ ما نُقَبِّلُ! فقال رسولُ اللهِ صلى الله عليه وسلم : «أَوَ أَمْلِكُ إن كانَ اللهُ نَزَعَ مِنْ قُلُوبِكُم الرَّحْمَةَ!».
‘Ā’ishah (may Allah be pleased with her) reported: Some Bedouins visited the Messenger of Allah (may Allah's peace and blessings be upon him) and they said: "Do you kiss your children?" He said: 'Yes.' They said: "By Allah we do not kiss our children." Thereupon the Messenger of Allah (may Allah's peace and blessings be upon him) said: "Then what can I do if Allah has removed mercy from your hearts?"
Explanation
Some Bedouins came to the Prophet (may Allah's peace and blessings be upon him) and (during their visit) they asked him: "Do you kiss your children?" The Prophet (may Allah's peace and blessings be upon him) replied: 'Yes.' Bedouins are normally harsh and rigorous, so they said: "We never kiss our children." So the Prophet (may Allah's peace and blessings be upon him) said: If Allah has removed mercy from your hearts, I would not be able to put it in them.
Source · Narrated by Bukhari & Muslim
From the Hadith Encyclopedia (hadeethenc.com).