Bhagavad Gita 6.7जितात्मनः प्रशान्तस्य परमात्मा समाहितः।शीतोष्णसुखदुःखेषु तथा मानापमानयोः ॥

The selfcontrolled Yogi who is rooted in the Self keeps poise amidst the pairs of opposites (Dvandvas) or the alternating waves of cold and heat, pleasure and pain, honour and dishonour. When the Yogi has subdued his senses, when his mind is balanced and peaceful under all conditions, when he is not in the least influenced by the pairts of opposites, when he has renounced all actions, then the Highest Self really becomes his own Self. He attains to Selfrealisation. As he rests in hiw own Self, he is ever serene or tranil he is not affected by the pairs of opposites, and he stands as adamant in the face of the changing conditions of Nature.