Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates this statement of the Prophet (peace and blessings of Allah be upon him): "When a person is performing prayer, he should not allow anyone to pass in front of him. He should try to keep him away as much as he can. If that (other person) does not comply, then he should fight with him, for that (other person) will be a devil."