The Messenger of Allah ﷺ said, "Tomorrow there will come to you a people whose hearts are more tender toward Islam than yours."Then the Asharis arrived, and among them was Abu Musa Ashari. As they drew near Medina, they began chanting in rajaz verse, saying, "Tomorrow we shall meet our beloved ones, Muhammad and his company."When they arrived, they shook hands with the people, and they were the first to introduce the practice of shaking hands.
قال رسول الله ﷺ: يقدم عليكم غدا أقوام، هم أرق قلوبا للإسلام منكم. قال: فقدم الأشعريون، فيهم أبو موسى الأشعري، فلما دنوا من المدينة جعلوا يرتجزون يقولون: غدا نلقى الأحبة محمدا وحزبه فلما أن قدموا تصافحوا، فكانوا هم أول من أحدث المصافحة.
Imam Ahmad (12582) narrated it, and Ibn Hibban (7193) graded it sahih, both through the route of Yahya bin Ayub, from Humayd Tawil, from Anas, who mentioned it. Its chain is sahih. It has other routes through Humayd, found in Ahmad (12026) and elsewhere.