Shiva Purana
अग्निहोत्रमुपादाय शेषान्न कृतभोजनः ॥ स वैश्यः क्षत्रियकुले जायते नात्र संशयः ॥ ११ ॥
He took the fire sacrifice and did not eat the rest. That vaisya is undoubtedly born in a kshatriya family.
english translation
agnihotramupAdAya zeSAnna kRtabhojanaH ॥ sa vaizyaH kSatriyakule jAyate nAtra saMzayaH ॥ 11 ॥
hk transliteration by Sanscript