Musnad Abu Ya'la al-Mawsili 147:28

Abu Khaythama narrated to us, Affan narrated to us, Hammad narrated to us, Humayd informed us, from Musa ibn Anas ibn Malik, from Anas, that the Messenger of Allah (may Allah bless him and grant him peace) said: "You have left behind in Medina men; you did not travel any distance, nor did you spend any expenditure, nor did you cross any valley, except that they were with you in it." They said: "O Messenger of Allah, how can they be with us while they are in Medina?" He said: "The excuse detained them."