(2) باب الإِمْسَاكِ بِالرُّكَبِ فِي الرُّكُوعِ
It was narrated that 'Abdur-Rahman As-Sulami said:
" 'Umar said: 'The Sunnah is to hold the knees.'" (ID)
Reference (ID): Sunan an-Nasa'i 1035 (ID)
In-book reference (ID): Book 12, Hadith 7 (ID)
English translation (ID): Vol. 2, Book 12, Hadith 1036 (ID)