(2) باب الإِمْسَاكِ بِالرُّكَبِ فِي الرُّكُوعِ
It was narrated that 'Umar said:
"It is established for you to hold the knees, so hold the knees." (ID)
Reference (ID): Sunan an-Nasa'i 1034 (ID)
In-book reference (ID): Book 12, Hadith 6 (ID)
English translation (ID): Vol. 2, Book 12, Hadith 1035 (ID)