The Hindu precept of 'cause no injury' applies to animals and all life forms. This precept isn't found in the oldest verses of Vedas (1500–1000 BCE), but increasingly becomes one of the central ideas in post-Vedic period. In the oldest layer of the Vedas, such as the "Rigveda", ritual sacrifices of animals and cooking of meat to feed guests are mentioned. This included goat, ox, horse and others (or may be misinterpretation of verses). However, the text is not uniform in the prescriptive sense. Some verses praise meat as food, while other verses in the Vedas also recommend "abstention from meat", in particular, "beef". According to Marvin Harris, the Vedic literature is inconsistent, with some verses suggesting ritual slaughter and meat consumption, while others suggesting a taboo on meat-eating.