Never,
because
"You can't be right by doing wrong; you can't be wrong by doing right."- Thomas S. Monson

What this quote is saying is that you can not be right by doing the wrong things and you can be wrong by doing the right things. For example, you are home alone and some friends come over and they throw a party but your mom and dad don't know that the right thing to do is tell your mom or just tell your friends. But lets say you let the throw the party are your mom finds out and you lie and say that it was not you and you did not know about it yes you did not throw the party yes you did not know that it was going to happen but if you told your mom or just told your friends no you would not be getting in trouble. What i'm trying to say is that when you do something bad or let something bad happen dose not mean you did the right thing because you would get in trouble or they will think you were part of it and you can not be right by doing something wrong. There is a big difference of being right when you do something right than being right when you do something bad.

            Right 

"If your so-called friends urge you do anything you know to be wrong, you be the one to make a stand for right, even if you stand alone. Have the moral courage to be a light for others to follow."-Thomas S. Monson 

What this quote is saying is that you don't have to do what your so-called friends tell you what do do if they want you to do the wrong thing you should stand for what is right even tho you will be standing alone be a light for some one else to follow don't be some one else shadow you should do what is right if you think it is right be your own light no matter if you will stand alone. Have the courage to stand alone if you will be choosing the right because you will end up being someone else role modal because you stood alone and choose what was right no matter if they called you names or made fun of u 

" Decisions Determine Destiny" Thomas S. Monson 

This quote means to me that what ever choices that you make it can determine what you do with your destiny and that it can affect you in a good way or a bad way. Also that you should choice whats you want your destiny to be like you can choice something good for you'r future or something bad. Like for example if you are going to get good grades for you can to college and you get all the good grades and you go to college that's a good decisions and its good for you and the choices you made made gave you a good future.