The Messenger of Allah ﷺ said, "How wretched it is for one of them, or one of you, to say, 'I have forgotten such-and-such a verse.' Rather, he was made to forget. Keep refreshing your memory of the Quran, for it slips away from the hearts of men faster than livestock escape from their tethers." The narrator said, or perhaps he said, "from its tether."
حدثنا عفان حدثنا حماد بن زيد حدثنا عاصم بن بهدلة وحدثنا منصور بن المعتمر عن أبي وائل
قال رسول الله ﷺ بئسما لأحدهم أو أحدكم أن يقول نسيت آية كيت وكيت بل هو نسي واستذكروا القرآن فإنه أسرع تفصيا من صدور الرجال من النعم من عقلها قال أو قال من عقله
Its isnad is sahih. Hammad bin Zayd narrated it from Asim bin Bahdala and Mansur bin Mutamir, both of them from Abu Waail. This hadith is a repetition of 4176 and is given at greater length at 4288."More swift in slipping away" Ibn Athir said, that is, "more swift in getting out." It is said, "I slipped away from the matter," meaning "I got out of it and freed myself from it."