In plain words
That is why they have been called the inner senses. But the outer senses act only through the urging and zeal of these inner senses. From the outward-turned senses we face no danger at all. But the outward-turned senses are driven by the inward-turned senses.
It is like this: a car has four tyres. It has lights in front. It has a petrol tank. All these are on the outside. But the steering alone is inside. Though these tyres run on the road outside, they turn only when the steering inside is turned; take hold of the tyres outside and turn them, and they will not turn. Our mind is the steering. Only when this inner sense called the mind turns do the outward legs and hands all keep turning. The lights are our eyes. These horns are our ears. The Front tyres are our hands. The back tyres are our legs. All these depend on the inner senses. So there is no use in our restraining the outward mouth, eyes and ears. In sleep we restrain them quite naturally. First of all we must try to control the mind. If this steering is in the right state, these senses will never take a wrong path. When at times the steering breaks down, these senses fall wherever they please. Manayeva manuṣyāṇāṃ kāraṇaṃ bandhamokṣayoḥ. So first of all we must try to understand the nature of the mind well.
We must not follow whatever the mind thinks. Next we must inquire with the Buddhi. Whatever your mind tells you, you must inquire with the Buddhi: Is it right or wrong, Is it good or bad. Today's students have no chance to travel as far as the Buddhi, poor things. The moment the mind thinks something, they go plunging into it foolishly. I am a student. I am an educated man. Is this work fit for me to do, or work unfit for me to do? Is this an honour to my position? Or a dishonour? I must show myself an ideal to all the citizens of this society. Being such a one, I must not enter any kind of bad path. I must live as a true ideal. We must develop good qualities.
Next, then, uparati. That is, we must keep the nature of the mind from journeying through the outward-turned senses and dwell for a while on the inward-turned feeling. One must inquire within oneself for a while: ‘Is my citta pure or not; are my feelings right or not?’ Only when one has self satisfaction within oneself should we strive for self sacrifice. But one does not find self satisfaction. In such a state, how can we lead our life in the outward world?