One verse

Srimad Bhagavatam 3.12.34

3.12.34

कदाचिद् ध्यायत: स्रष्टुर्वेदा आसंश्चतुर्मुखात् । कथं स्रक्ष्याम्यहं लोकान् समवेतान् यथा पुरा ॥ ३४ ॥

kadacid dhyayatah srastur veda asams catur-mukhat katham sraksyamy aham lokan samavetan yatha pura

kadacit
once upon a time
dhyayatah
while contemplating
srastuh
of Brahma
vedah
the Vedic literature
asan
became manifested
catuh-mukhat
from the four mouths
katham sraksyami
how shall I create
aham
myself
lokan
all these worlds
samavetan
assembled
yatha
as they were
pura
in the past.

Once upon a time, when Brahma was thinking of how to create the worlds as in the past millennium, the four Vedas, which contain all varieties of knowledge, became manifested from his four mouths.