The Śūraṅgama Sūtra, Volume 10: The Delusive Conception of Luminous Emptiness

Original text: 即此所说。临高想心。能令汝形。真受酸涩。由因受生。能动色体。汝今现前。顺益违损。二现驱驰。名为虚明。第二妄想。

Explanation: The delusive thinking mind just described—imagining oneself standing at the edge of a cliff—can cause a genuine sensation of soreness and astringency in the soles of your feet. Because of the arising of this inner feeling, it can induce changes in the material body. For instance, in the two phenomena just described, your mind feels as though the sour object and the cliff are right in front of you, and thus changes occur in the body. When you now encounter favorable circumstances that benefit the body, a comfortable feeling arises; and when you encounter adverse conditions that harm the body, a painful feeling arises. These two phenomena are called the second delusion, the false illumination (virtual luminosity) delusion.

This is saying that the aggregate of feeling (vedanā) is a delusion of false illumination, and it is also an error of delusive thinking, and therefore it is not real. If one clings to the aggregate of feeling, there will be the suffering of birth and death in saṃsāra, and one will not be liberated from afflictions.