The only aim of life is to increase happiness.
What I feel becomes me. That is why a surgeon gravitates to a better position in the scheme of the creation than a murder, even though they both engage in cutting others open. All sins are committed against the self.
The desire for survival is very strong in all living beings. This translates into need for safety and comfort. The craving for gratification is the root of all sins.
By doing something, if my heart aches, I am defying my heart. When I steal, I feel guilt. This emotion is the desire for punishment. Now I have deemed myself worthy of punishment.
In conflicting circumstances we should choose the smaller evils; a solder must kill, and a spy must steal. To a dying person or to a child, a lie may be a lot better than the brutal truth. If the only way to stop some one from killing a loved one is to kill the assailant, we must kill him.
I know that I should not steal the million, just to gratify my senses. Would I do it, if I had the opportunity? I don't know for sure. I hope not. Our desires exert immense pull on us momentarily. Succumbing to temptations and avoiding temptations, both are habits. It will depends on how deep rooted the habit of avoiding temptation is, as compared to the expected potential gratification.
Let mercy guide us in all situations. The mercy we feel is proportional to our emotional attachment to the person involved. A woman may give her life to save her child, but not to save a neighbor's child. But the mercy that
I feel for myself is sin. In other words, I should try to remove 'ME' from the equation of life, and be satisfied with what comes to me rightfully. If I can feel more mercy for the millionaire, than for me, I win.
Again, the act of not stealing I perform is for my selfish interest. The only thing, is that, now I have defined my self interest correctly.