My dear Uddhava, the material universe that you perceive through your mind, speech, eyes, ears and other senses is an illusory creation that one imagines to be real due to the influence of māyā. In fact, you should know that all of the objects of the material senses are temporary.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
यदिदं मनसा वाचा चक्षुर्भ्यां श्रवणादिभिः । नश्वरं गृह्यमाणं च विद्धि मायामनोमयम्
yadidaṃ manasā vācā cakṣurbhyāṃ śravaṇādibhiḥ | naśvaraṃ gṛhyamāṇaṃ ca viddhi māyāmanomayam
SB 11.7.7