Bhagavad Gita 2.25

अव्यक्तोऽयमचिन्त्योऽयमविकार्योऽयामुच्यते |
तस्मादेवं विदित्वैनं नानुशोचितुमर्हसि

Translation

The soul is spoken of as invisible, inconceivable, and unchangeable. Knowing this, you should not grieve for the body.