Vaisesika Sūtra 6.1.15

समे आत्मत्यागः परत्यागो वा ॥१५॥

samē ātmatyāgaḥ paratyāgō vā ॥15॥

[समे (samē) - in the equal; आत्म-त्यागः (ātma-tyāgaḥ) - relinquishment of self; पर-त्यागः-वा (para-tyāgaḥ-vā) - or renunciation of other;]

Among equals, relinquishment of self-interest or of another occurs.