بُلُوغُ الْمَرَامِ
Bulugh al-Maram 399
The Book of Prayer
وَلَهُمَا عَنْ أَبِي هُرَيْرَةَ: { بِخَمْسٍ وَعِشْرِينَ جُزْءًا } [1] .
Both al-Bukhari and Muslim have also reported through Abu Hurairah (RA): "Twenty-five degrees (more)."
Sunnah.com reference: Book 2, Hadith 303