Bhagwad Gita
Chapter 2, Verse 25
अव्यक्तोऽयमचिन्त्योऽयमविकार्योऽयमुच्यते।
तस्मादेवं विदित्वैनं नानुशोचितुमर्हसि।।2.25।।
It is said that the soul is invisible, inconceivable, immutable, and unchangeable. Knowing this, you should not grieve for the body.