At the end of the Age of Kali, these two kings, having received instruction directly from the Supreme Personality of Godhead, Vāsudeva, will return to human society and reestablish the eternal religion of man, characterized by the divisions of varṇa and āśrama, just as it was before.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
ताविहैत्य कलेरन्ते वासुदेवानुशिक्षितौ । वर्णाश्रमयुतं धर्मं पूर्ववत्प्रथयिष्यतः
tāvihaitya kalerante vāsudevānuśikṣitau | varṇāśramayutaṃ dharmaṃ pūrvavatprathayiṣyataḥ
SB 12.2.38