Happiness and sorrow, decrepitude and death, gain and loss, the agreeable and the disagreeable,-these form the nineteenth principle and are called pairs of opposites.
सुखासुखे जरामृत्यू लाभालाभौ प्रियाप्रिये। इति चैकोनविंशोऽयं द्वन्द्वयोग इति स्मृतः॥