Musnad Abu Ya'la al-Mawsili 115:162

Abu Musa narrated to us, Muhammad bin Ja'far narrated to us, Shu'bah narrated to us, from Qatadah, from Anas, that the Messenger of Allah (may Allah bless him and grant him peace) used to say: "O Allah, indeed the life is the life of the Hereafter, so honor the Ansar and the Muhajirun."