There is a system by which one can detect an incarnation of the Supreme Personality of Godhead. Nowadays it has become a cheap fashion to accept any rascal as an incarnation of God, but from this incident we can see that Lord Brahma personally examined the hands and feet of King Prthu for specific signs. In their prophecies the learned sages and brahmanas accepted Prthu Maharaja as a plenary partial expansion of the Lord. During the presence of Lord Krsna, however, a king declared himself Vasudeva, and Lord Krsna killed him. Before accepting someone as an incarnation of God, one should verify his identity according to the symptoms mentioned in the sastras. Without these symptoms the pretender is subject to be killed by the authorities for pretending to be an incarnation of God.