In plain words
At this age students follow the mind alone. They do not travel as far as the Buddhi. That is why they fall into all kinds of troubles and losses. They fall into unrest and discontent. They fall into despair and dejection. So you must enquire with the Buddhi: ‘Where should I do what, and what should I not do; when should I go and when should I not; I am a human being, an educated man: at what level and in what way must I act to win respect?’ To behave like one without learning, though educated, is a path against humanness. So follow the path that befits your learning. Humility is the chief adornment of learning. Without that humility, learning has no grace at all. That is why this discrimination, when, where, how and by what path to proceed, is essential for a devotee.
The fifth is determination, firm resolve. This determination is a good rein. Whatever we have set our mind on, we must strive to achieve it with determination, giving no room to doubts and no opening to misgivings. Do not give room to the doubt, ‘Will I achieve what I have to achieve, or not?’ When your determination is firm, there is nothing in this world you cannot achieve. The very first is Dedication; the last is Determination, firm resolve. At the one end tyāga; at the other sādhana, that is, winning through. This is determination. Without these two, the ones in between are of no use to us at all. However much Bhakti you have, however much enquiry you make, however many disciplines you take up, without these two it is all wasted. Without feet below and a head above, what would you do with a trunk alone? Do not depend on your own cleverness. Do not depend on your own power of intellect. Recognise the truth that God alone is the support of all this. Only then shall we have rightly understood this principle of Bhakti.