بُلُوغُ الْمَرَامِ
Bulugh al-Maram 235
The Book of Prayer
وَفِي رِوَايَةٍ : { فَإِنَّ مَعَهُ اَلْقَرِينَ } [1] .
In another narration: "for there is a Satan with him."
Sunnah.com reference: Book 2, Hadith 102
The Book of Prayer
In another narration: "for there is a Satan with him."