One verse

Srimad Bhagavatam 9.5.27

9.5.27

इत्येतत् पुण्यमाख्यानमम्बरीषस्य भूपते । सङ्कीर्तयन्ननुध्यायन् भक्तो भगवतो भवेत् ॥ २७ ॥

ity etat punyam akhyanam ambarisasya bhupate sankirtayann anudhyayan bhakto bhagavato bhavet

iti
thus
etat
this
punyam akhyanam
most pious activity in history
ambarisasya
of Maharaja Ambarisa
bhupate
O King (Maharaja Pariksit)
sankirtayan
by chanting, repeating
anudhyayan
or by meditating upon
bhaktah
a devotee
bhagavatah
of the Supreme Personality of Godhead
bhavet
one can become.

Anyone who chants this narration or even thinks of this narration about the activities of Maharaja Ambarisa certainly becomes a pure devotee of the Lord.