Chapter 2 · The Yoga of Knowledge · Krishna said
Bhagavad Gita 2.38 — Equal in win and loss
सुखदुःखे समे कृत्वा लाभालाभौ जयाजयौ। ततो युद्धाय युज्यस्व नैवं पापमवाप्स्यसि ॥
sukhaduḥkhe same kṛtvā lābhālābhau jayājayau | tato yuddhāya yujyasva naivaṃ pāpamavāpsyasi ||
Meaning
Treat pleasure and pain, gain and loss, victory and defeat as the same, and then get ready to fight. Fighting in this way, you will not incur sin.
In today's life
Give your best to an exam or a match without letting the result decide your peace of mind.