manasaiva pure devah
manasa bhagavan ajah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The omnipotent Yamaraja is as good as Lord Brahma, for while situated in his own abode or in everyone’s heart like the Paramatma, he mentally observes the past activities of a living entity and thus understands how the living entity will act in future lives.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
One should not consider Yamaraja an ordinary living being. He is as good as Lord Brahma. He has the complete cooperation of the Supreme Lord, who is situated in everyone’s heart, and therefore, by the grace of the Supersoul, he can see the past, present and future of a living being from within. The word anumimamsate means that he can decide in consultation with the Supersoul. Anu means “following.” The actual decisions concerning the next lives of the living entities are made by the Supersoul, and they are carried out by Yamaraja.