Rig Veda 9.73.5
piturmAturadhyA ye samasvarannR^ichA shochantaH sandahanto avratAn.h |
indradviShTAmapadhamanti mAyayA tvachamasiknIM bhUmano divaspari |
VAlmIki (cursing the hunter) uttered with grief the shloka in the anushhTubh meter of 32 syllables. These anushhTubh verses of the rAmAyaNa, with the fire of grief (the shoka-agni of vAlmIki), burn up the body full of tamas as well as the mUla-avidyA, and liberate the AtmA which has become sorrowful due to repeated births in various wombs. For this reason, vAlmIki is dearer than even parents (to their children) because he has filled the rAmAyaNa with instructions that are even more beneficial than instructions of parents!
Rig Veda 9.73.6
pratnAnmAnAdadhyAye samasvaraJN.h chhlokayantrAso rabhasasya mantavaH |
apAnakShAso badhirA ahAsata R^itasya panthAM na taranti duShkR^itaH ||
VAlmIki, having understood the Veda and with supernatural vision, created the rAmAyaNa poem with the device of shlokas (shlokayantra) based on what he had heard from nArada. The origin of shloka is described. Having seen the evil deed (of the hunter), VAlmIki uttered a curse " Those who are under the control of the currents of the mind, ie. desire, anger, etc., who are devoid of the discrimination between good and evil deeds, who have not heard the scriptures and are thus deaf, and who have gone astray from the path of truth, will not cross over misery because of the results of their sins."
The famous shloka that vAlmIki utters when he witnesses the killing of the krauncha bird by the hunter:
mA niShAda pratiShThA.n tvamagamaH shAshvatI.n samAH |
yatkrauJNchamithunAdekamavadhIH kAmamohitam.h ||
O Hunter! Since you killed one of the pair of Krauncha birds in love, you shall never attain fame!
Since this verse was born of VAlmIki's grief (shoka), it was called "shloka","shokArtasya pravR^itto me shloko bhavatu nAnyathA".