AN 4.191 This is why the oral tradition is the way to go (recite suttas everyday)

AN 4.191. Followed by Ear

191. Sotānugatasutta	191. Followed by Ear
“Sotānugatānaṃ, bhikkhave, dhammānaṃ, vacasā paricitānaṃ, manasānupekkhitānaṃ, diṭṭhiyā suppaṭividdhānaṃ cattāro ānisaṃsā pāṭikaṅkhā.	“monks, you can expect four benefits when the teachings have been followed by ear, reinforced by recitation, examined by the mind, and well comprehended theoretically.
Katame cattāro?	What four?
Idha, bhikkhave, bhikkhu dhammaṃ pariyāpuṇāti—	Take a monk who memorizes the teaching—
suttaṃ, geyyaṃ, veyyākaraṇaṃ, gāthaṃ, udānaṃ, itivuttakaṃ, jātakaṃ, abbhutadhammaṃ, vedallaṃ.	statements, songs, discussions, verses, inspired sayings, legends, stories of past lives, amazing stories, and analyses.
Tassa te dhammā sotānugatā honti, vacasā paricitā, manasānupekkhitā, diṭṭhiyā suppaṭividdhā.	They’ve followed those teachings by ear, reinforced them by recitation, examined them by the mind, and well comprehended them theoretically.
So muṭṭhassati kālaṃ kurumāno aññataraṃ devanikāyaṃ upapajjati.	But they die unrememberful and are reborn in one of the orders of gods.
Tassa tattha sukhino dhammapadā plavanti.	Being happy there, passages of the teaching come back to them.
Dandho, bhikkhave, satuppādo;	Memory comes up slowly,
atha so satto khippaṃyeva visesagāmī hoti.	but then that being quickly reaches distinction.
Sotānugatānaṃ, bhikkhave, dhammānaṃ, vacasā paricitānaṃ, manasānupekkhitānaṃ, diṭṭhiyā suppaṭividdhānaṃ ayaṃ paṭhamo ānisaṃso pāṭikaṅkho.	This is the first benefit you can expect when the teachings have been followed by ear, reinforced by recitation, examined by the mind, and well comprehended theoretically.
Puna caparaṃ, bhikkhave, bhikkhu dhammaṃ pariyāpuṇāti—	Take another monk who memorizes the teaching—
suttaṃ, geyyaṃ, veyyākaraṇaṃ, gāthaṃ, udānaṃ, itivuttakaṃ, jātakaṃ, abbhutadhammaṃ, vedallaṃ.	statements, songs, discussions, verses, inspired sayings, legends, stories of past lives, amazing stories, and analyses.
Tassa te dhammā sotānugatā honti, vacasā paricitā, manasānupekkhitā, diṭṭhiyā suppaṭividdhā.	They’ve followed those teachings by ear, reinforced them by recitation, examined them by the mind, and well comprehended them theoretically.
So muṭṭhassati kālaṃ kurumāno aññataraṃ devanikāyaṃ upapajjati.	But they die unrememberful and are reborn in one of the orders of gods.
Tassa tattha na heva kho sukhino dhammapadā plavanti;	Though they’re happy there, passages of the teaching don’t come back to them.
api ca kho bhikkhu iddhimā cetovasippatto devaparisāyaṃ dhammaṃ deseti.	However, a monk with psychic powers, who has achieved mastery of the mind, teaches Dhamma to the assembly of gods.
Tassa evaṃ hoti:	They think:
‘ayaṃ vā so dhammavinayo, yatthāhaṃ pubbe brahmacariyaṃ acarin’ti.	‘I used to live the spiritual life in this same teaching and training.’
Dandho, bhikkhave, satuppādo;	Memory comes up slowly,
atha so satto khippameva visesagāmī hoti.	but then that being quickly reaches distinction.
Seyyathāpi, bhikkhave, puriso kusalo bherisaddassa.	Suppose a person was an expert in the sound of drums.
So addhānamaggappaṭipanno bherisaddaṃ suṇeyya.	While traveling along a road they hear the sound of drums.
Tassa na heva kho assa kaṅkhā vā vimati vā:	They wouldn’t have any doubts or uncertainties about whether
‘bherisaddo nu kho, na nu kho bherisaddo’ti.	that was the sound of drums or not.
Atha kho bherisaddotveva niṭṭhaṃ gaccheyya.	They’d just conclude, ‘That’s the sound of drums.’
Evamevaṃ kho, bhikkhave, bhikkhu dhammaṃ pariyāpuṇāti—	In the same way, take another monk who memorizes the teaching …
(the remaining two cases are similar, with varying degree of remembering)