When one of you prays, he should not let anyone pass in front of him; he should turn him away as far as possible; but if he refuses (to go), he should fight him, for he is only a devil.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ إِذَا كَانَ أَحَدُكُمْ يُصَلِّي فَلاَ يَدَعْ أَحَدًا يَمُرُّ بَيْنَ يَدَيْهِ وَلْيَدْرَأْهُ مَا اسْتَطَاعَ فَإِنْ أَبَى فَلْيُقَاتِلْهُ فَإِنَّمَا هُوَ شَيْطَانٌ  

When one of you prays, he should pray facing the sutrah (screen or covering) and he should keep himself close to it. He then narrated the tradition to the same effect.  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا صَلَّى أَحَدُكُمْ فَلْيُصَلِّ إِلَى سُتْرَةٍ وَلْيَدْنُ مِنْهَا ثُمَّ سَاقَ مَعْنَاهُ  

I saw 'Ata b. Yazid al-Laithi praying in a standing posture. So I went to him passing in front of him; he, therefore, turned me away. He then said to me: Abu Sa'id al-Khudri reported the Messenger of Allah ﷺ as saying: If anyone of you can do that he should not let anyone pass between him and the qiblah, he should do it.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنِ اسْتَطَاعَ مِنْكُمْ أَنْ لاَ يَحُولَ بَيْنَهُ وَبَيْنَ قِبْلَتِهِ أَحَدٌ فَلْيَفْعَلْ  

I narrate what I witnesses from Abu Sa'id and heard from him. Abu Sa'id entered upon Marwan and said: I heard the Messenger of Allah ﷺ say: When one of you prays facing any object which conceals him from people, and someone wishes to pass in front of him, he should strike him at his chest; if he refuses (to go), he should fight him; he is only a devil. Abu Dawud said: Sufyan Ath-Thawri said: "A person arrogantly walks in front of me while I am praying, so I stop him, and a weak person passes, so I dont stop him."  

أَبُو صَالِحٍ أُحَدِّثُكَ عَمَّا رَأَيْتُ مِنْ أَبِي سَعِيدٍ وَسَمِعْتُهُ مِنْهُ دَخَلَ أَبُو سَعِيدٍ عَلَى مَرْوَانَ فَقَالَ سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ إِذَا صَلَّى أَحَدُكُمْ إِلَى شَىْءٍ يَسْتُرُهُ مِنَ النَّاسِ فَأَرَادَ أَحَدٌ أَنْ يَجْتَازَ بَيْنَ يَدَيْهِ فَلْيَدْفَعْ فِي نَحْرِهِ فَإِنْ أَبَى فَلْيُقَاتِلْهُ فَإِنَّمَا هُوَ شَيْطَانٌ