Musnad Ahmad 33:1069

Surayj narrated to us, Hushaym narrated to us, from Abu Bishr, from Abu Sufyan, from Jabir ibn Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) entered upon some of his family and said: "Do you have any condiment?" They said: "No, except for some vinegar." He said: "Bring it." He began to dip [his food] into it and said: "What an excellent condiment vinegar is."