2.65 Prasade, when there is serenity; upajayate, there follows; hanih, eradication; asya sarva-duhkhanam, of all his, the sannyasin's, sorrow on the physical and other planes. Moreover, (this is so) hi, because; buddhih, the wisdom; prasanna-cetasah, of one who has a serene mind, of one whose mind is poised in the Self; asu, soon; pari-avatisthate, becomes firmly established; remains steady (avatisthate) totally (pari), like the sky, i.e. it becomes unmoving in its very nature as the Self.
The meaning of the sentence is this: Since a person with such a poised mind and well-established wisdom attains fulfilment, therefore a man of concentration [A man who is free whom slavery to objects of the senses.] ought to deal with the indispensable and scripturally non-forbidden objects through his senses that are free from love and hatred.
That same serenity is being eulogized: