SB 11.19.7

tvayy uddhavāśrayati yas tri-vidho vikāro
 māyāntarāpatati nādy-apavargayor yat
janmādayo ’sya yad amī tava tasya kiṁ syur
 ādy-antayor yad asato ’sti tad eva madhye
Synonyms: 
tvayi — in you; uddhava — O Uddhava; āśrayati — enters and remains; yaḥ — which; tri-vidhaḥ — in three divisions, according to the modes of nature; vikāraḥ — (the material body and mind, which are subject to) constant transformation; māyā — illusion; antarā — during the present; āpatati — suddenly appears; na — not; ādi — in the beginning; apavargayoḥ — nor at the end; yat — since; janma — birth; ādayaḥ — and so on (growth, procreation, maintenance, dwindling and death); asya — of the body; yat — when; amī — these; tava — in relation to you; tasya — in relation to your spiritual nature; kim — what relationship; syuḥ — could they have; ādi — in the beginning; antayoḥ — and in the end; yat — since; asataḥ — of that which does not exist; asti — exists; tat — that; eva — indeed; madhye — only in the middle, at present.
Translation: 
My dear Uddhava, the material body and mind, composed of the three modes of material nature, attach themselves to you, but they are actually illusion, since they appear only at the present, having no original or ultimate existence. How is it possible, therefore, that the various stages of the body, namely birth, growth, reproduction, maintenance, dwindling and death, can have any relation to your eternal self? These phases relate only to the material body, which previously did not exist and ultimately will not exist. The body exists merely at the present moment.
Purport: 

The example is given that a man walking in the forest may see a rope but consider it to be a snake. Such perception is māyā, or illusion, although the rope actually exists and a snake also exists in another place. Illusion thus refers to the false identification of one object with another. The material body exists briefly and then disappears. In the past the body did not exist, and in the future it will not exist; it enjoys a flickering, momentary existence in so-called present time. If we falsely identify ourselves as the material body or mind, we are creating an illusion. One who identifies himself as American, Russian, Chinese, Mexican, black or white, man or woman, communist or capitalist, and so on, accepting such designations as his permanent identity, is certainly in deep illusion. He can be compared to a sleeping man who sees himself acting in a different body while dreaming. In the previous verse Lord Kṛṣṇa told Uddhava that spiritual knowledge is the means of achieving the highest perfection, and now the Lord is explicitly describing such knowledge.