Musnad Ahmad 31:593

Isma'il narrated to us, Sa'id informed us, from Abu Nadra, from Abu Sa'id, who said: We had just conquered Khaybar when we, the companions of the Messenger of Allah (may Allah bless him and grant him peace), fell upon that vegetable—garlic—and we ate a great deal of it, for we were hungry people. Then we went to the mosque, and the Messenger of Allah (may Allah bless him and grant him peace) sensed the odor. He said: "Whoever has eaten anything of this foul vegetable, let him not approach us in the mosque." Some people said: "It has been forbidden! It has been forbidden!" This reached the Messenger of Allah (may Allah bless him and grant him peace), so he said: "O people, it is not for me to forbid what Allah has made lawful, but it is a plant whose odor I dislike."