Chapter IV Sloka 01

Aw ctuwaeR=Xyay>, }ankmRs<Nyasyaeg>, 

ïI-gvanuvac, 

#m< ivvSvte yaeg< àaeKtvanhmVyym!, 
ivvSvaNmnve àah mnuirúvakve=ävIt! .

atha caturtho'dhy˜ya×| (jñ˜nakarmasanny˜sayoga×)

þrŸbhagav˜nuv˜ca | 

imaÕ vivasvate yogaÕ 
proktav˜nahamavyayam | 
vivasv˜nmanave pr˜ha 
manurikÿv˜kave'bravŸt ( 4|01)||

The Blessed Lord said:

I taught this imperishable Yoga to Vivasvan; he told it to Manu; Manu proclaimed it to Ikshvaku.

Commentary

Vivasvan means the sun . Ikshvaku was the son of Manu and the reputed ancestor of the solar dynasty of Kshatriyas.
This Yoga is said to be imperishable because the result or fruit, i.e., Moksha, that can be attained through it is imperishable.
If the rulers of dominions possess knowledge of the Yoga taught by Me in the preceding two discourses, they can protect the Brahmanas and rule their kingdom with justice. So I taught this Yoga to the Sun-god at the beginning of evolution.