What is the ruling on the imam placing a sutrah in front of him while praying in the mihrab, and what is the distance that should be covered in front of the worshiper?

It is sunnah for the worshiper, whether an imam or praying alone, to place a sutrah in front of him to prevent people from passing and to aid in khushu' (devotional humility). This applies to both travel and residence, and to both obligatory and supererogatory prayers. The wisdom behind it is to restrain the gaze and prevent passersby. The command to use a sutrah is for recommendation, not obligation. What diverts the command from obligation is the action of the Prophet, peace and blessings be upon him, who prayed in a desert without a sutrah. Accordingly, the Hanafis and Malikis affirmed its sunniyyah (being sunnah) if one fears someone passing, while the Shafi'is and Hanbalis broadly affirmed its sunniyyah without qualification. The sutrah can be a wall, a pillar, or similar objects, and the worshiper should be close to it. There is disagreement regarding the distance between the worshiper and his sutrah; some say three cubits, and others say six cubits.