SB 7.3.23

sa tat kīcaka-valmīkāt
 vajra-saṁhanano yuvā
utthitas tapta-hemābho
 vibhāvasur ivaidhasaḥ
saḥ — Hiraṇyakaśipu; tat — that; kīcaka-valmīkāt — from the anthill and bamboo grove; sahaḥ — mental strength; ojaḥ — strength of the senses; bala — and sufficient bodily strength; anvitaḥ — endowed with; sarva — all; avayava — the limbs of the body; sampannaḥ — fully restored; vajra-saṁhananaḥ — having a body as strong as a thunderbolt; yuvā — young; utthitaḥ — arisen; tapta-hema-ābhaḥ — whose bodily luster became like molten gold; vibhāvasuḥ — fire; iva — like; edhasaḥ — from fuel wood.
As soon as he was sprinkled with the water from Lord Brahmā’s waterpot, Hiraṇyakaśipu arose, endowed with a full body with limbs so strong that they could bear the striking of a thunderbolt. With physical strength and a bodily luster resembling molten gold, he emerged from the anthill a completely young man, just as fire springs from fuel wood.

Hiraṇyakaśipu was revitalized, so much so that his body was quite competent to tolerate the striking of thunderbolts. He was now a young man with a strong body and a very beautiful bodily luster resembling molten gold. This is the rejuvenation that took place because of his severe austerity and penance.