The Messenger of Allah ﷺ said, "Whenever two Muslims meet and one takes the hand of the other, it becomes binding upon Allah to be present for their supplication, and He will not part their hands until He has forgiven them both."
حدثنا محمد بن بكر حدثنا ميمون المرائي حدثنا ميمون بن سياه
عن رسول الله ﷺ قال ما من مسلمين التقيا فأخذ أحدهما بيد صاحبه إلا كان حقا على الله أن يحضر دعاءهما ولا يفرق بين أيديهما حتى يغفر لهما
Its isnad is hasan. Both men named Maymun have some discussion about them. Maymun Murai, with fatha on the meem and without the alif according to most, is Maymun bin Musa, while Maymun bin Siyah, Abu Bahr Basri, is truthful but makes mistakes.The hadith is found in Abu Dawud, 4/354, number 5212, in the Book of Manners, chapter on handshaking, and in Tirmidhi, 5/74, number 2727, in the Book of Seeking Permission, with similar wording, where he said, hasan gharib. It is also in Ibn Majah, 2/1220, number 3703, similar to the version in Abu Dawud.