Musnad Ahmad 32:931

Yahya narrated to us, from Humayd, from Anas, who said: When we returned from the expedition of Tabuk, the Prophet (peace and blessings of Allah be upon him) said: "Indeed, there are people in Medina who, you did not cross a valley, nor did you travel a path, but they were your partners in it." They said: "Even though they were in Medina?" He said: "The excuse detained them."