Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 47


जन्मादयस्तु देहस्य विक्रियानात्मन: क्व‍‍चित् ।कलानामिव नैवेन्दोर्मृतिर्ह्यस्य कुहूरिव ॥ ४७ ॥


janmādayas tu dehasyavikriyā nātmanaḥ kvacitkalānām iva naivendormṛtir hy asya kuhūr iva


Birth and other transformations are undergone by the body but never by the self, just as change occurs for the moon’s phases but never for the moon, though the new-moon day may be called the moon’s “death.”


Lord Balarāma here explains how the conditioned souls identify with the body and how this identification should be given up. Certainly every ordinary person considers himself or herself young, middle-aged or old, healthy or sick. But such identification is an illusion, just as the waxing and waning of the moon is an illusion. When we identify ourselves with the material body, we lose our power to understand the soul.