[NOTE: The complete sutta gives similes for the five hindrances as well as a simile of a mind without hindrances. If you have time it is worth reading the whole sutta. We can contemplate these similes not only in regards to memorization but also meditation in general.]
At Savatthī. Then the brahmin Saṅgarava approached the Blessed One and exchanged greetings with him. When they had concluded their greetings and cordial talk, he sat down to one side and said to the Blessed One:
“Master Gotama, what is the cause and reason why sometimes even those hymns that have been recited over a long period do not recur to the mind, let alone those that have not been recited? What is the cause and reason why sometimes those hymns that have not been recited over a long period recur to the mind, let alone those that have been recited?”
…“Again, brahmin, when one dwells with a mind obsessed by ill will, overwhelmed by ill will, and one does not understand as it really is the escape from arisen ill will, on that occasion one neither knows nor sees as it really is one’s own good, or the good of others, or the good of both. Then even those hymns that have been recited over a long period do not recur to the mind, let alone those that have not been recited.
“Suppose, brahmin, there is a bowl of water being heated over a fire, bubbling and boiling. If a man with good sight were to examine his own facial reflection in it, he would neither know nor see it as it really is.
“So too, brahmin, when one dwells with a mind obsessed by ill will, overwhelmed by ill will, and one does not understand as it really is the escape from arisen ill will, on that occasion one neither knows nor sees as it really is one’s own good, or the good of others, or the good of both.
…
Read the entire translation of Saṁyutta Nikāya 46.55 Saṅgāravasutta: Saṅgarava by Bhikkhu Bodhi on SuttaCentral.net. Or read a different translation on SuttaCentral.net. Or listen on SC-Voice.net. Or explore the Pali on DigitalPaliReader.online.