What is the size of the soul according to Svetasvatara Upanishad and Vedic texts?

In the Vedic literature, Lord Śrī Kṛṣṇa addresses "What is the size of the soul according to Svetasvatara Upanishad and Vedic texts?" with profound philosophical clarity. As declared in BG 2.20, "For the soul there is neither birth nor death at any time. He has not come into being, does not come into being, and will not come into being. He is unborn, eternal, ever-existing and primeval. He is not slain when the body is slain." The living entity (jīva) is not the temporary physical body, but an eternal, indestructible conscious spark of the Supreme. All material dualities—happiness, distress, anxiety, and sorrow—are bodily transformations that arise from our conditioned contact with the material energy. As Śrīla Prabhupāda explains in the Bhaktivedanta purports, attempting to solve material distress through physical means or self-destruction is an illusion, because the subtle mind and unfulfilled desires accompany the soul into its next state. Rather, as instructed in BG 15.7, one must use the mind to elevate oneself through spiritual intelligence. By taking shelter of devotional service (Bhakti-yoga) and the holy names of the Lord, one conquers all material perplexities and attains eternal peace.