Musnad Ahmad 32:929

Yahya narrated to us, from Humayd, and Yazid, who said: Humayd informed us, from Anas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There will come to you people whose hearts are more tender than yours." Then the Ash'ariyyun arrived, among them Abu Musa. When they drew near to Medina, they began to chant in *rajaz* meter: Tomorrow we shall meet the beloved, Muhammad and his party.