SB 8.19.39

satyaṁ puṣpa-phalaṁ vidyād
 ātma-vṛkṣasya gīyate
vṛkṣe ’jīvati tan na syād
 anṛtaṁ mūlam ātmanaḥ
Synonyms: 
satyam — the factual truth; puṣpa-phalam — the flower and the fruit; vidyāt — one should understand; ātma-vṛkṣasya — of the tree of the body; gīyate — as described in the Vedas; vṛkṣe ajīvati — if the tree is not living; tat — that (puṣpa-phalam); na — not; syāt — is possible; anṛtam — untruth; mūlam — the root; ātmanaḥ — of the body.
Translation: 
The Vedas enjoin that the factual result of the tree of the body is the good fruits and flowers derived from it. But if the bodily tree does not exist, there is no possibility of factual fruits and flowers. Even if the body is based on untruth, there cannot be factual fruits and flowers without the help of the bodily tree.
Purport: 

This śloka explains that in relation to the material body even the factual truth cannot exist without a touch of untruth. The Māyāvādīs say, brahma satyaṁ jagan mithyā: “The spirit soul is truth, and the external energy is untruth.” The Vaiṣṇava philosophers, however, do not agree with the Māyāvāda philosophy. Even if for the sake of argument the material world is accepted as untruth, the living entity entangled in the illusory energy cannot come out of it without the help of the body. Without the help of the body, one cannot follow a system of religion, nor can one speculate on philosophical perfection. Therefore, the flower and fruit (puṣpa-phalam) have to be obtained as a result of the body. Without the help of the body, that fruit cannot be gained. The Vaiṣṇava philosophy therefore recommends yukta-vairāgya. It is not that all attention should be diverted for the maintenance of the body, but at the same time one’s bodily maintenance should not be neglected. As long as the body exists one can thoroughly study the Vedic instructions, and thus at the end of life one can achieve perfection. This is explained in Bhagavad-gītā: yaṁ yaṁ vāpi smaran bhāvaṁ tyajaty ante kalevaram. Everything is examined at the time of death. Therefore, although the body is temporary, not eternal, one can take from it the best service and make one’s life perfect.