DEUT1235 R. Shimon says: The Egyptians, who drowned Israel in the Nile, and the Edomites, who went out against Israel with the sword, were forbidden by Scripture only until the third generation, whereas the Amonites and Moavites, who took counsel to make Israel sin, were forbidden by Scripture forever -- to teach that one who causes another to sin is worse than one who kills him; for one who kills him removes him only from this world, whereas one who causes him to sin removes him even from the next world (Sifrei)