Question
Why does Isvara tell pArvati 'Sri rAma rAma rAma iti rame rAme manorame sahasra nAma tatulyam rAma nAma varAnane".
Answer
When pArvati questions iSvara, if there is any simpler way to recite the sahasra nAma of Vishnu, iSvara answers in the above way. Often people translate, interpret this sloka in the way they wish.-TBT
Interesting interpretation, and I agree. Raama is the essence of all mantras, especially the combination of the two letters ra (from the Narayana Astakshari) and ma (from the Siva Panchakshari).
This sloka is not part of the phalasruti of the Vishnu Sahasranama in the Mahabharata. It is taken from the Padmapurana, as part of the phalasruti of the (different) Vishnu Sahasranama in that Purana. However, as a sloka appropriate for daily recital, the Sishtas of yore included it in the parayana krama of the Vishnu Sahasranama of the Mahabharata, at the very end of the phalasruti.
In the sloka the question asked by parvati devi is "kenopayena laghunaa vishnornaama sahasrakam padyathe panditair nityam srothumichamyaham prabho"
ie, is there an easy way for
the panditas to recite the thousand names of lord Vishnu daily.
the name pandita is defined by Adi Sankaracharya as
panda Atmavishayaa buddhiryeshaam te hi panditaah.' (Bhagavad Gita Bhashyam 2.11).
So the answer by Ishwara is applicable to such panditas.
Whereas the Vishnu Sahasranama that is frequently chanted, from the Mahabharata, is a response to some queries from Yudhishtira, like
stuvantam kam prapnuyuh manavaah subham? (ie, meant for all
maanavaas,
whether panditas or not)
kam arcanat praapnuyuh maanavaah subham? (ie, for all
maanavaas)
kim japam mucyathe jantur janma samsaara bandhanaath? (for
all creatures)
The name Raama itself is also found inside the Vishnu Sahasranama (raamo viraamo...) so it is anyway recited when one recites the Sahasranama.