Muwatta Malik, Book 47, Hadith 16 (USC-MSA)

Yahya related to me from Malik from Ata ibn Abi Muslim that Abdullah al-Khurasani said, "The Messenger of Allah, may Allah bless him and grant him peace, said, 'Shake hands and rancour will disappear. Give presents to each other and love each other and enmity will disappear.' "

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ عَطَاءِ بْنِ أَبِي مُسْلِمٍ عَبْدِ اللَّهِ الْخُرَاسَانِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ تَصَافَحُوا يَذْهَبِ الْغِلُّ وَتَهَادَوْا تَحَابُّوا وَتَذْهَبِ الشَّحْنَاءُ ‏" ‏ ‏.‏

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also referenced under: Book 47, Hadith 1651 (In-Book)