Yogācārabhūmi-śāstra, Fascicle 34 (14)

Original text: 云何寻思内事形色。所作变异无常之性。谓如说显色。如是形色由肥瘦故。应知亦尔。云何寻思内事兴衰。所作变异。无常之性。谓由观见。或自或他。先时眷属财位。或见悉皆兴盛。后见一切皆悉衰损。复于后时还见兴盛。见是事已便作是念。如是诸行其性无常。何以故。兴衰变异。现可得故。

Explanation: How does one contemplate the impermanent nature of the changes occurring in the forms and features of internal matters? Just as with the manifest colors that have been observed, so it should be known for forms and features with regard to fatness and thinness. How does one contemplate the impermanent nature of the changes occurring in the flourishing and decline of internal matters? By observing oneself or others: in earlier times, one's retinue, wealth, and status might all be seen to flourish; later, everything is seen to decline and diminish; and after that, one sees flourishing again. Having observed these phenomena, one then has this thought: such conditioned formations are truly impermanent in nature. Why? Because the flourishing and decline of family wealth and retinue can be directly observed in the present.