What should a worshiper do if someone passes in front of him while he is praying, whether in individual or congregational prayer?

A worshipper, whether praying alone or as an Imam, is commanded by Islamic law to place a Sutrah (an object used as a barrier) in front of him. It is Sunnah (definition) (recommended) for him to repel anyone who attempts to pass between him and his Sutrah, or close to him if he does not have a Sutrah. A follower (Ma'mum) should repel anyone who passes between him and his Imam, because the Imam serves as a Sutrah for him. However, he should not repel anyone who passes in front of the Imam. Scholars derive this from the Hadith (definition) of Umm Salamah (may Allah be pleased with her) and the Hadith of Abu Sa'id, agreed upon by both Bukhari and Muslim: "If any of you prays facing something that screens him from the people, and someone wants to pass in front of him, then he should repel him; if he insists, he should fight him, for he is a devil." The meaning of "fight him" here is to exert effort in repelling him without invalidating the prayer. If the passerby does not retreat or the worshipper does not repel him, his prayer remains valid.