Sahih Bukhari
Fighting for the Cause of Allah (Jihaad)
Volume: 004 / Book Number: 052 / Hadith Number: 304
Narrated Jabir bin Abdullah:
I said, "O Allah's Apostle! We have slaughtered a young sheep of ours and have ground one Sa of barley. So, I invite you along with some persons." So, the Prophet said in a loud voice, "O the people of the Trench! Jabir had prepared "Sur" so come along."