Yogācārabhūmi Śāstra, Volume 34 (17)

Original text: 云何寻思内事他所损害。所作变异。无常之性。谓由观见或自或他他所损害。其身变异。或由刀杖鞭革。皮绳矛槊等坏。或由种种蚊虻蛇蝎。诸恶毒触之所损害。复于余时。见不变异。见是事已。便作是念。如是诸行。其性无常。余如前说。

Explanation: How does one contemplate the impermanent nature of the changes that occur when the internal matters of one's own body are harmed by others? By observing that oneself or others, having been harmed by others, undergo changes in the body—either destroyed by knives, staffs, whips, leather, sturdy ropes, spears, lances, and the like, or harmed by the venomous touches of various mosquitoes, gnats, snakes, scorpions, and other poisonous creatures—yet later one sees the body has recovered, with no more signs of change. After observing these phenomena, one forms this thought in the mind: such volitional formations are truly impermanent.