Verse 8.5.4

तद्य एवैतवरं च ण्यं चार्णवौ ब्रह्मलोके ब्रह्मचर्येणानुविन्दन्ति तेषामेवैष ब्रह्मलोकस्तेषां सर्वेषु लोकेषु कामचारो भवति ॥ ८.५.४ ॥
॥ इति पञ्चमः खण्डः ॥

tadya evaitavaraṃ ca ṇyaṃ cārṇavau brahmaloke brahmacaryeṇānuvindanti teṣāmevaiṣa brahmalokasteṣāṃ sarveṣu lokeṣu kāmacāro bhavati || 8.5.4 ||
|| iti pañcamaḥ khaṇḍaḥ ||

4. When they attain through brahmacarya the two oceans, Ara and Ṇya, in Brahmaloka, that Brahmaloka is theirs, and they can then move freely in all the worlds.

Word-for-word explanation:

Tat ye, those who; etau arṇavau, these two oceans; aram ca ṇyam ca, Ara and Ṇya; brahmaloke, in Brahmaloka; anuvindanti, attain; brahmacaryeṇa, through brahmacarya; teṣām eva, for them; eṣaḥ brahmalokaḥ, is this Brahmaloka; sarveṣu lokeṣu, in all the worlds; teṣām kāmacāraḥ bhavati, they can go freely. Iti pañcamaḥ khaṇḍaḥ, here ends the fifth section,

Commentary:

Brahmaloka is not a physical region like this earth. It is a state of being. It is next to liberation. You are almost free there, but not quite.

Vedānta says there are four states. The first and the highest is when a person merges immediately into Brahman at the time of death. The next state is Brahmaloka. After that is Svargaloka, heaven. This is where people who have done good things go after death. They are very happy there, but they must eventually come back to earth.

The majority of people, however, fall into the fourth category. After death they must immediately come back to this world. They have desires, and in order to fulfil their desires they must have a body.