One verse

Srimad Bhagavatam 1.3.6

1.3.6

स एव प्रथमं देव: कौमारं सर्गमाश्रित: । चचार दुश्चरं ब्रह्मा ब्रह्मचर्यमखण्डितम् ॥ ६ ॥

sa eva prathamam devah kaumaram sargam asritah cacara duscaram brahma brahmacaryam akhanditam

sah
that
eva
certainly
prathamam
first
devah
Supreme Lord
kaumaram
named the Kumaras (unmarried)
sargam
creation
asritah
under
cacara
performed
duscaram
very difficult to do
brahma
in the order of Brahman
brahmacaryam
under discipline to realize the Absolute (Brahman)
akhanditam
unbroken.

First of all, in the beginning of creation, there were the four unmarried sons of Brahma (the Kumaras), who, being situated in a vow of celibacy, underwent severe austerities for realization of the Absolute Truth.