Musnad Ahmad 31:526

Waki' narrated to us, al-A'mash narrated to us, from Abu Salih, from Abu Sa'id al-Khudri, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Do not revile my companions, for by Him in Whose hand is my soul, if one of you were to spend the equivalent of Mount Uhud in gold, he would not reach a mudd of one of them, nor half of it."