Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Hudhayfah bin Yaman (may Allah be pleased with him) that the Noble Prophet (peace and blessings of Allah be upon him) said: "When a believer meets another believer, greets him with salam, and shakes hands with him, their sins fall away like the leaves of a tree."

Sayyiduna Bara bin Azib (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "When two Muslims meet each other and shake hands, before they part, they are forgiven."