śrī-śuka uvāca
nanda-vrajaḿ gate rāme
karūṣādhipatir nṛpa
vāsudevo 'ham ity ajño
dūtaḿ kṛṣṇāya prāhiṇot
sri-sukah uvaca -- Sukadeva Gosvami said; nanda -- of Nanda Maharaja; vrajam -- to the cowherd village; gate -- having gone; rame -- Lord Balarama; karusha-adhipatih -- the ruler of Karusha (Paundraka); nripa -- O King (Parikshit); vasudevah -- the Supreme Lord, Vasudeva; aham -- I; iti -- thus thinking; ajnah -- foolish; dutam -- a messenger; krishnaya -- to Lord Krishna; prahinot -- sent.
Since Lord Rama had gone to Nanda-vraja, Paundraka foolishly thought that Lord Krishna would be alone and therefore easy to challenge. Thus he dared to send his crazy message to the Lord.