Advice for his son Rav Reuven on becoming 20 years old

Igros Moshe (YD III 96.9) Advice for  his son Rav Reuven  on becoming 20 years old You  write that on the 11th of Elul you will be twenty years old – you should have a long life which is good and sweet –this is the age that there is punishment for sins also from Heaven. You ask  advice as to how to behave the rest of your life . The most important thing is being strongly working in studying the Torah.  Rashi notes that one can easily err and for a Torah scholar this is considered a deliberate sin. Therefore G-d should help you to grow in Torah and to know everything clearly and this will lead to doing the right thing. Thus your entire purpose and goal in this world is that your entire lifes’s effort are in Torah.  If you do this I am confident that G-d will help you and send you a generous parnossa and plentiful blessing which are presents from G-d according to one’s merit and they are not the result of a job. You should not accept this G-d forbid – as an oath which is prohibited – but it should be your mental commitment. You should also train yourself in good attributes. The main thing is to avoid anger which is to be greatly avoided as well as excessively pride  If you try hard G-d will help you Also this should not be accepted as an oath. You should also be very careful with honoring your mother. This is something which is extremely difficult  since you have been familiar since childhood and thus it requires great effort. Even if she is forgiving disrespect you should not rely on that. You also ask about fasting. It is not proper for you and those involved in Torah study because it might interfere.  Instead of afflicting yourself, you should increase your Torah study. You should be constantly aware of my words and G-d should help you always.