Virtues of the Prayer Hall (Sutra of the Musalla)
Bukhari :: Book 1 :: Volume 9 :: Hadith 488
Narrated Abu Salih As-Samman:
I saw Abu Said Al-Khudri praying on a Friday, behind something which acted as a Sutra. A young man from Bani Abi Mu'ait, wanted to pass in front of him, but Abu Said repulsed him with a push on his chest. Finding no alternative he again tried to pass but Abu Said pushed him with a greater force. The young man abused Abu Said and went to Marwan and lodged a complaint against Abu Said and Abu Said followed the young man to Marwan who asked him, "O Abu Said! What has happened between you and the son of your brother?" Abu Sa'id said to him, "I heard the Prophet saying, 'If anybody amongst you is praying behind something as a Sutra and somebody tries to pass in front of him, then he should repulse him and if he refuses, he should use force against him for he is a satan.' "