One verse

Srimad Bhagavatam 3.10.9

3.10.9

एतावाञ्जीवलोकस्य संस्थाभेद: समाहृत: । धर्मस्य ह्यनिमित्तस्य विपाक: परमेष्ठ्यसौ ॥ ९ ॥

etavan jiva-lokasya samstha-bhedah samahrtah dharmasya hy animittasya vipakah paramesthy asau

etavan
up to this
jiva-lokasya
of the planes inhabited by the living entities
samstha-bhedah
different situations of habitation
samahrtah
performed completely
dharmasya
of religion
hi
certainly
animittasya
of causelessness
vipakah
mature stage
paramesthi
the highest personality in the universe
asau
that.

Lord Brahma is the most exalted personality in the universe because of his causeless devotional service unto the Lord in mature transcendental knowledge. He therefore created all the fourteen planeary divisions for inhabitation by the different types of living entities.