Mishkat al-Masabih 18 The Offices of Commander and Qadi كتاب الإمارة والقضاء 32

وَعَنْ أَنَسٍ قَالَ: كَانَ قَيْسُ بْنُ سَعْدٍ مِنَ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِمَنْزِلَةِ صاحبِ الشُّرَطِ منَ الأميرِ. رَوَاهُ البُخَارِيّ

Anas said that Qais b. Sa‘d had a position in relation to the Prophet like that of a prefect of a district in relation to a governor. Bukhari transmitted it.