Reference: al-Jaami’ lil-Khateeb – Volume 2, Page 250
al-Hifth – Ahammiyyatuhu, ‘Ajaa.ibuhu, Tareeqatuhu, Asbaabuhu – Page 8
‘Abdur-Razzaaq ibn Hammaam said:
Any knowledge which cannot accompany its possessor to the toilet is not considered knowledge.
Translator’s note: This statement indicates only that which is memorised is considered knowledge.