N:  In original text, instead of word austerities stands Tapas.
 

The Three Austerities, Physical, Vocal and Mental

Physical austerity refers to using the body to perform good actions, which includes worshipping the Lord and expressing your sense of gratitude by serving great souls. If you earn their grace, the selfish aspects of I-ness and my-ness will slowly get reduced. Once these negative qualities decline, then automatically positive qualities and actions will develop. At that point, you will naturally be attracted to the company of like-minded spiritual beings and be inspired to study the Gita and other sacred texts.

In addition to this, you will undertake charity for education, for medicine and hospitals, for poor feedings and other good causes. And just as, traditionally, the different types of charities such as giving away gold and cows and land were the means for using the body in sacred activities, so also you will now be using your body in a sacred way. Since you will not be doing any harmful or prohibited activities, you will not put yourself under the spell of the sense of doership and possessiveness. You will free yourself from bondage to these two qualities. All of this can be described as bodily penance.

Vocal penance is the use of good and noble words. Even when you speak the truth you should not be severe or sharp-tongued. You must be careful not to hurt anyone. In this context, the Gita has said that truth must be sweet and nonviolent. Use the sacred tongue which has been given to you for giving joy and delight to others and for helping them. Do not give any suffering to another's mind. Use your thoughts to help you concentrate and think of the Lord. Use your tongue to describe all the glorious attributes of the Lord. Use words which are highly helpful to others. Use your talk to show the right path to others. Explain to others all the great and good spiritual experiences that you have had. Correct people if they are going on the wrong path by using good words and a sweet tongue. Make sure that no amount of falsehood enters your heart, or enters your talk. This is the way to become an adept of truth and nonviolence.

Better Be Quiet Than Tell An Untruth

If you are following the path of truth there may be quite a few problems that you will encounter. A particular sage performing penance had taken an oath to take the path of truth and nonviolence, come what may. A cruel hunter who heard of this tried to induce the sage to break his vow. The hunter pursued a deer and drove it in such a way that it had to pass in front of the sage, immersed in his austerities. The sage saw the deer hiding in the bush. The hunter came running and asked the sage, "Have you seen a deer passing this way?" The sage was in great conflict. If he told the truth he would cause harm to the deer, but if he did not tell the truth he would be breaking his vow. On the one hand, he would commit the sin of causing harm to another being, and on the other hand, he would commit the sin of lying.

The sage found a very good way of dealing with this dilemma. He answered the hunter's query in a somewhat enigmatic way. He said, "The eyes which see cannot speak and the mouth which speaks cannot see. I cannot make that which has seen speak, and that which can speak see. That is the truth." Even in such difficult situations one should not tell an untruth, but one may not be able to tell the truth either. When you are engaged in the vocal type of austerity, difficult situations of this kind may arise. You should make every effort to see to it that you escape without uttering any falsehood. Whatever be the circumstances, do not tell a lie. If you cannot tell the truth then it is best for you to keep quiet and observe silence, rather than uttering an untruth. Consider the third austerity, the mental austerity. In this type of austerity you will have to develop good qualities and virtues. Whatever thoughts may be flashing through your mind, your face will show the reflection of them. That is why it is said that the face is the index of the mind. All thoughts will be reflected on your face. If you are grief-stricken mentally, your face will reflect that state. If there are sacred thoughts in your mind your face will be very cheerful. The effect of the mind and its thoughts can easily be seen in this way.

Only when you have sacred thoughts, sacred feelings and sacred ideas in your mind, will you be able to live a happy and cheerful life. If there are bad thoughts torturing you, then whenever somebody comes and talks to you, even if you try to smile, your smile will be artificial and it will betray the disturbed inner state in your heart. You should not allow yourself to be driven to such a state. Always keep yourself happy. When will you be happy and joyous? Only when your thoughts are good and sacred. In order to have such good and sacred thoughts in your mind you should exercise control over your thoughts.

Every Day Observe A Period Of Silence

At least for a few hours a day you should observe silence. Then the mind will get some rest from words and thought waves. Repetition of the holy name and concentration on the Lord can also be practiced to give some rest to the mind. Repetition of the name and thinking of the Lord brings about both inner and outer purity. Just as you bathe your body every day and transform it into a clean outer vehicle, the mind, too, has to be given a regular purification bath to renew its freshness and sacredness. Now you are concerned mostly with physical cleanliness, but you must also engage in mental cleanliness, which is equally essential to life. Good thoughts, good feelings and good actions go a long way to bring about inner cleanliness.

Austerity truly means bringing about a physical, vocal and mental unity by letting actions words and thoughts become one. This is the real austerity. A great soul is one who has been able to enjoy the unity of all these three attributes. If the thoughts, the words, and the actions are different, then a person cannot be considered a great person.