One verse

Srimad Bhagavatam 4.23.4

4.23.4

तत्राप्यदाभ्यनियमो वैखानससुसम्मते । आरब्ध उग्रतपसि यथा स्वविजये पुरा ॥ ४ ॥

tatrapy adabhya-niyamo vaikhanasa-susammate arabdha ugra-tapasi yatha sva-vijaye pura

tatra
there
api
also
adabhya
severe
niyamah
austerities
vaikhanasa
rules and regulations of retired life
su-sammate
perfectly recognized
arabdhah
beginning
ugra
severe
tapasi
austerity
yatha
as much as
sva-vijaye
in conquering the world
pura
formerly.

After retiring from family life, Maharaja Prthu strictly followed the regulations of retired life and underwent severe austerities in the forest. He engaged in these activities as seriously as he had formerly engaged in leading the government and conquering everyone.