न प्रहृष्येत्प्रियं प्राप्य नोद्विजेत्प्राप्य चाप्रियम्।
स्थिरबुद्धिरसम्मूढो ब्रह्मविद्ब्रह्मणि स्थितः।।5.20।।
।।5.20।। जो स्थिरबुद्धि संमोहरहित ब्रह्मवित् पुरुष ब्रह्म में स्थित है वह प्रिय वस्तु को प्राप्त होकर हर्षित नहीं होता और अप्रिय को पाकर उद्विग्न नहीं होता।।
Agreeable and disagreeable situations occur in accordance to the physical body one happens to dwell in and the karma or reactions to past life actions an embodied being is subjected to which both exemplify the grave risks of material existence. A person who would seek to scale the heights of spiritual knowledge should remain equiposed at all times and not feel elation at receiving something agreeable nor feel dejection at receiving something disagreeable. How is this possible? It is possible for one who is sthira-buddhir meaning steadfast intelligence. Such a person plants his mind and will in the stability of the atma or soul. The word asammudho means not subject to delusion. If one is sammudho they are inflicted with delusion in the form of confusing the stable eternal atma with the unstable temporary body. How can one escape this delusion? If a person is brahma- vid or a knower of the spiritual substratum pervading all existence from instruction and brahmani sthitah or perceiving and experiencing the spiritual substratum pervading all existence every moment. The meaning Lord Krishna is conveying is that those who receive instructions from the bonafide spiritual preceptor in one of the four authorised sampradayas or line of disciplic succession shall learn the exact nature and means of attainment of the eternal atma. This is brahma-vid. Such a one through diligent and sincere application of this spiritual knowledge always remembering and honouring the spiritual preceptor who mercifully gave such knowledge. In due course of time one will achieve atma tattva or realisation of the soul and in such an elevated position one will blissfully commune internally with the eternal atma and the eternal spiritual preceptor as well and from thenceforth nothing in the external world will ever again be perceived as being agreeable or being disagreeable.