Hadith 1745
Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) narrates: On the day of the Battle of Khandaq, the Prophet (peace and blessings of Allah be upon him) said, "These people did not let us perform the middle prayer. May Allah fill their homes and bellies with fire." (The narrator says) This was the Asr prayer.
Hadith 1746
Sayyiduna Abdullah narrates that the Prophet Muhammad (peace be upon him) said: "The middle prayer refers to the Asr prayer."