In plain words
What kind of people they mix with, what kind of society they live in: this we must find out. When a fellow is keeping bad company, we should not so much as look at his face. Even if he says "Hello, hello", we must say "good bye" and go away. The friendship of such people is a danger to our life.
But the students of today, through education of a worldly kind, are all turning into nothing but friends. This cannot be called true friendship. Passing clouds. Who knows at what minute it will drift apart! Such friendship lasts just so far and no further. "Hello" when someone says "Hello", then "good bye, good bye": you must say that and end it there. Besides this, at this age virtue is of the first importance for students. Without it one is just a corpse whose life has gone. Do not make friends with one who has no character. Such people have no individual character. They have no social character. When there is no social character, how can national character come? First of all, man must have individual character. That is, we must cultivate a Manas that does not waver and a vision that is not deluded. If a man swings this way and that over everything, like the pendulum of a clock, do not so much as look at the face of such a one. Make no friendship at all with such a man. In the end you too will turn bad. So we must make the effort to befriend good people. When iron gets into the earth, it rusts and loses its strength. Iron is firm and hard. Once that same iron gets into the fire, it turns bright. Even a blow of the hand draws it out. When one joins good company, the heart becomes sacred, as if it had entered the fire. The moment the rust leaves it, it is pure. Once it is pure, we can work it in the fitting way. We can make such iron into any shape, a semicircle or a circle. So every human being must be refined.
What does being refined mean? Separating out the impurity in it. Fostering virtue. All the things we eat in this world are produced by nature. We eat rice. We eat split pulses. We eat all sorts of other things besides. We do not eat them just as they came into being. Paddy ripens. We have to separate out the straw.