bhuktam hanti tri-purusam
prasahya tu balad bhuktam
dasa purvan dasaparan
If a person enjoys a brahmana’s property without receiving due permission, that property destroys three generations of his family. But if he takes it by force or gets the government or other outsiders to help him usurp it, then ten generations of his ancestors and ten generations of his descendants are all destroyed.
According to Srila Sridhara Svami, tri-purusa refers to oneself, one’s sons and one’s grandsons.