यद्दुरापं दुराराध्यं दुराधर्षं दुरुत्सहम्।

तत्सर्वं तपसा शक्यं तपो हि दुरतिक्रमम्।।

Whatever is difficult to obtain, hard to meditate upon, difficult to control and complex to endure, all that is possible by penance. Indeed the power of penance is unconquerable.

तद्विद्धि प्रणिपातेन परिप्रश्नेन सेवया।

उपदोक्ष्यन्ति ते ज्ञानं ज्ञानिनस्तत्वदर्शिनः।।

O Arjuna! For gaining knowledge from the philosophers and the experienced scholars, you will have to approach them with polite salutations, questioning and guru’s service. Then only they will guide you.

यथा चतुर्भिः कनकं परीक्ष्यते

निघर्षणच्छेदनतापताडनैः।

तथा चतुर्भिः पुरुषः परीश्र्यते

श्रुतेन शीलेन कुलेन कर्मणा।।

Just as the gold is tested in four means (rubbing, cutting, heating and pounding), similarly a man is tested on the basis of four things (knowledge, behavior, race and actions).